French onion soup is one of my earliest memories of eating in a restaurant.

I was with my mother and grandmother. I forget which one ordered soup, but when it came to the table, my grandmother encouraged me to try it.

The savory broth was enough to win me over. But what attracted me most was the top layer of toast and cheese, which had absorbed some of the broth underneath.

It took me years to try my vegan French onion soup recipe, but I finally did. I’m glad I did.

Like all French soups, this one will require your patience, but I promise you won’t regret it.

What is French onion soup?

French onion soup is a soup made with Onions that have been caramelized and stewed in a broth.

French onion soup can be served with toast or croutons and cheese.

The history of a humble soup

When I started thinking about making French onion soup at home, I wondered if it was a French dish or an American one inspired by the characteristics of French cuisine.

As it turns out, French onion soup does come from France.

Onion soup has been enjoyed for centuries. However, the version we are familiar with did not take shape until the 19th century.

Les Halles, the famous Paris food market, and some restaurants around it began serving French onion soup topped with toast and cheese.

According to author Emily Monaco, French onion soup is not only a long-cherished antidote to alcoholism but also a historically egalitarian dish eaten by Parisians of all classes. Thanks to the often inexpensive ingredients, the soup was accessible to many people for most of history.

In the late 19th century, French onion soup became famous worldwide. It became known as “French onion soup” in England in the 1880s and first appeared in an American restaurant in 1861.

A variation on French onion soup

Most French onion soup recipes call for caramelizing Onions with fat and then simmering them in a liquid.

The liquid can be broth alone or a thick soup with added flour. Occasionally, I’ve seen variations that call for milk or cream.

As for toppings can be large croutons topped with grated cheese or small pieces of cheese toast.

The bread can be cut into cubes or lumps, or it can be small slices of baguette.

Cheese, meanwhile, is usually gruy<e:1> cheese. However, I’ve seen recipes calling for Emmantal, Parmesan, Asiago, and mozzarella.

This vegetarian French onion soup allows you to use homemade melted cashew cheese or commercial vegan shredded cheese.

I’ve tried both versions, and they give me different kinds of pleasure. Homemade cheese turns an irresistible brown in the oven, while the commercial version melts and stretches more easily.

When making this soup, I tried to add various ingredients to the soup base: carrots, celery, and herbs.

In the end, I liked and shared a purist version. This classic vegetarian French onion soup is all Onions, which is what it should be.

Caramelize the onion

Making a good pot of French onion soup comes down to one critical process: caramelizing the onion.

Honestly, there are so many articles on properly caramelizing onions that I feel almost foolish offering my information.

However, the amount of guidance on this topic is overwhelming, so it may be valuable to extract some essential points.

First: What does it mean to caramelize an onion?

Caramelizing Onions is cooking Onions over low (mild) heat for a long time.

The long, slow cooking process oxidizes or browns the natural sugars in Onions, giving them a sweet, nutty flavor.

This is the production of caramel. The same caramelization happens if you make candy or caramel sauce with a solution of sugar and water. In this case, it happens with the natural sugars in vegetables.

What’s the difference between caramelization and roasting?

Suppose you’ve ever roasted Onions in the oven or over high heat. In that case, you’ve probably seen that Onions almost always start to turn brown.

What’s the difference between Browning and caramelization?

The difference comes down to two factors: time and temperature.

Caramelized Onions cook longer at lower temperatures than Satam Onions. As a result, their sugars oxidize more thoroughly and take on a more profound sweetness.

Fried or roasted Onions will turn brown, but they usually retain more flavor and spiciness than caramelized Onions.

How long does it take to caramelize Onions?

In general, it takes 40-60 minutes to caramelize Onions. A small batch of Onions may take less time, while a large batch will take longer.

Every time I make this vegetarian French onion soup, it takes me about 50 minutes to completely caramelize the Onions.

Tips and tricks for caramelizing Onions

Caramelized Onions is a culinary topic that inspires strong opinions. I won’t pretend to have authoritative or expert guidance, but I’ve found a few tips that are very useful and worth sharing.

Tip 1: Don’t let your emotions run high

When you’ve been stirring a pot of Onions every few minutes for more than half an hour, it’s tempting to turn up the heat to cook the Onions faster.

Try to resist the urge. Raising the temperature will brown the food, but that’s not quite the same as caramelizing.

If you don’t allow this low, slow effect, you may end up with charred Onions instead of caramelized ones.

Tip 2: Choose a cooker with a broader bottom

Since the caramelized Onions in this recipe will turn into vegetarian French onion soup, you’ll need to cook them in a large, heavy-based pot. I recommend using a pot with a relatively wide diameter rather than a tall, narrow stockpot.

If you are making your own caramelized Onions, I recommend placing a large, deep skillet on top of it.

Why? The larger the surface area, the more Onions can be exposed to heat and cooked slowly.

A narrower pot will also work but requires more stirring and may take more time.

Tip 3: Stir every 10 minutes (or so)

Stir the Onions moderately as they caramelize.

If you stir too much, the onion will not be able to contact the heat source and develop a nice brown color.

If you stir too little, the onion will start to burn and become bitter instead of caramelizing and becoming sweet and fragrant.

It is appropriate to stir every 8-10 minutes. Stir enough time to keep the Onions moving and ensure they all touch the bottom of the pan. But there’s also plenty of rest to help them all turn brown.

Can I caramelize the onion in a non-stick pan?

When I moved some time ago, I bought a set of coriander, non-toxic ceramic non-stick cookware. It was a significant investment, and I’ve been thrilled with my cookware since then. (You can find my full review here.)

As I prepared to make this vegetarian French onion soup, I wondered if the non-stick surface would be a problem. I have often read that better options exist than a non-stick pan for cooking Onions.

There may be better choices than non-stick cookware for caramelizing Onions, but it can do the job.

The main difference is the time it takes to start caramelization. Compared to stainless steel or cast iron, non-stick Onions take longer to see their true brown color.

Eventually, however, time and heat will work their magic, and the onion will caramelize. Have faith in the process!

Do I need to add sugar to the Onions?

Many guidelines for caramelizing Onions instruct home cooks to add sugar.

Sugar helps advance the caramelization process and adds extra caramel flavor to onions.

When I make caramelized Onions, I don’t plan on making them into a soup, but I do add a little brown sugar (and some balsamic vinegar at the end).

However, I don’t think the sugar adds anything or flavor to this soup, so there’s no need to add it.

What kind of onion should I use?

You can use any kind of onion in a pinch. I caramelized red, white, yellow, and sweet Onions.

Sweet Onions are my favorite for caramel, but I’ve also used white Onions many times. You can even use shallots – although you’ll need many for this recipe!

Olive oil vs. vegan butter

Some French onion soup recipes call for butter as a fat source, while others call for oil.

This recipe calls for quite a bit of broth – a full eight cups.

Another thing about broth is that it shouldn’t be cold. Use room-temperature broth or broth prepared with hot water. If you’re recreating broth cubes or meat powder, you’ll use hot liquid anyway.

How to make vegetarian French onion soup

As you begin this recipe, remember patience. It is not difficult, but it is a commitment. Knowing this beforehand lets you relax, get comfortable with the process, and enjoy it.

Step 1: Chop the onion

Be prepared to spend some time making this, as this soup requires about 3 pounds of Onions!

To cut Onions for your vegetarian French onion soup, you’ll trim them neatly and cut them in half lengthwise.

Then, thinly slice the onion with a slicer or chef’s knife. The slice from root to stem should be 3/16-1/4 inch / 4-6mm wide.

Step 2: Caramelize the onion

This is an important step.

First, heat the olive oil in a large, heavy-based pot over medium-high heat. Add onion and salt.

First, the Onions will fill the pan almost completely. When you stir and coat them with oil, they soften and become smaller.

Cover the pan and begin caramelizing, stirring the Onions every 10 minutes. The process should take 40-60 minutes.

Step 3: Add garlic and white wine

Once the Onions are perfectly browned, it’s time to season them and start making the base of the soup.

Garlic and white wine – dried, I recommend – are part of the process. You can skip the wine altogether, but I wouldn’t recommend skipping the garlic.

Step 4: Add a little flour

If you add a small amount of flour to thicken the soup at this point, it will become richer.

Lightly dust the onion with two tablespoons of all-purpose flour (plain or gluten-free). Cook for a few minutes, stirring constantly, or until the onion has thickened and the flour is slightly cooked.

Slowly add 1 cup of broth, stirring as it cooks. Then, add the remaining broth, two bay leaves, and a dash of vinegar to the pan.

Step 5: Simmer

Turn the heat up, cook the soup, then turn the heat down. Cover and simmer for 30 minutes. Remove the bay leaves and taste the soup, adjusting the salt and pepper to your liking.

Step 6: Make cheese toast

Now it’s time to prepare those delicious grinsame cheese toasts.

I offer two cheese options for toast. One is my delicious vegan cashew mozzarella.

The cheese is creamy and a little elastic. It’s very general; I use it to top grilled lasagna or seashells, my vegan broccoli melts, and pizza.

Once you’ve made a batch of cheese, you’ll spread it – be sure to spread it on pre-toasted slices of bread while the cheese is hot.

I bake bread in the oven. A minute or two per side is enough. When it returns to the oven, it cooks even better with cheese on top.

The bread you use can be round, triangular, or sandwich-shaped. You can also use a baguette sliced horizontally.

If you don’t have time to make your own vegan cheese, that’s no problem. Many good, commercial vegan shredded cheeses that melt and stretch are available today.

My favorite is Good Planet Foods’ shredded Mozzarella, but many other brands also make this cheese.

You don’t have to use store-bought shredded cheese; you can also use a few slices of vegetarian mozzarella, American cheese, or Gouda.

After spreading the cheese on the bread, put it in the oven for 3-4 minutes or until the cheese is baked and melted.

Step 7: Top the soup with cheese toast

At this point, you will divide the soup into bowls or molds and top each portion with cheese toast.

The toast will cover all the soup if you use a smaller container, such as a ramekin. However, if you use a large bowl, the cheese toast may be partially submerged in the soup.

Make-ahead option

Vegetarian French onion soup is an excellent choice for preparation and advanced cooking.

The soup can be stored in an airtight container in the refrigerator for up to a week or frozen for up to 6 weeks.

If you’re making melted cashew mozzarella, it can be stored in an airtight container in the refrigerator for up to four days.

It thickens in the fridge, but that’s okay. When you are ready to bake bread, spread it directly on the bread.

How do you pair it with vegetarian French onion soup?

The soup was so hearty and warm that it could serve as a potluck.

However, I always like to have a vegetable side dish or two with any main course. Here are a few, mainly salads, that I think pair well with the vegetarian French onion soup:

• Quick steamed green beans with Dijon vinaigrette
• My favorite butter lettuce on a side salad
• Crispy broccoli Caesar salad
• The perfect chopped winter salad
• Winter salad
• Brussels sprouts salad
• Broccoli and pomegranate kale salad
• Radicchio sprouts salad

However you choose to serve this historic and comforting soup, I hope you’ll enjoy it.

Ingredients

2 tablespoons olive oil

3 extra large or 4 regular large Onions *(3-3/2lb / 1.4-1.5kg)

1/2 teaspoon salt

2 cloves garlic, minced

1 cup dry white wine (240ml); You can omit it if you wish.)

2 tablespoons unbleached all-purpose flour (substitute gluten-free all-purpose flour or ultra-fine brown rice flour)

2 quarts vegetarian beef or vegetable broth, room temperature (1.9L)

Two bay leaves

1 tablespoon white balsamic vinegar (instead of 2 teaspoons sherry vinegar)

6 slices of half sourdough or peasant bread (or 6 slices of horizontal baguette)

1 lot melted vegetarian cashew mozzarella cheese (instead of 1 1/2 cups store-bought vegan mozzarella shredded or 6 vegan mozzarella slices or Gouda slices)

Instructions

Prepare soup

1. Use a slicer or chef’s knife to slice the onion thinly. The slice from root to stem should be 3/16-1/4 inch / 4-6mm wide.
2. Heat the oil in a large, heavy-based pot over medium heat. Add the onion and salt. The Onions will fill the pan almost completely. Stir the onion in the pan to spread the oil, then cover and cook for 5 minutes. Uncover and stir. Reduce the heat to medium and cover the pan again.
3. Continue cooking the Onions in the covered pot until they caramelize. This will take a total of 40-60 minutes. Remove the lid from the onion and stir every 10 minutes, adjusting the temperature if necessary. Every time you stir the Onions, you will notice they are Browning at the bottom of the pan. Stir well and let the caramel spread out – it’s delicious! However, if the Onions start to burn, turn down the heat. Ultimately, you want the whole onion to be dark golden, tender, and much smaller.
4. Add the garlic to the pan, stirring as it cooks, and cook for 1-2 minutes or until fragrant. Add the white wine to the pot and let it simmer. Continue to cook for 5 minutes, stirring frequently, or until most of the liquid has evaporated.
5. Lightly sprinkle the flour over the onion and stir. Continue cooking and stirring for a few minutes or until the flour is evenly absorbed and the onion thickens. Slowly pour in the broth, 1 cup / 240 ml at a time, stirring as it cooks. When all the broth has been added to the pot, add the bay leaves and vinegar and cover the pot. Turn the heat high, bring the soup to a simmer, then reduce the heat again. Cover and simmer for 30 minutes.
6. Remove the bay leaves from the pot and taste the soup. Adjust the salt as needed and season with freshly ground black pepper.

Prepare the cheese toast.

1. If it’s homemade, make vegetarian cashew mozzarella now.
2. Turn your broiler up. Place the bread slices on a tin foil-lined baking sheet and bake in the oven for 2 minutes on each side until they are almost golden brown. Take the bread out of the oven and spread a layer of homemade cashew cheese on each slice. Alternatively, spread your store-bought vegan cheese on slices of bread. Return the bread to the oven and bake for another 3-4 minutes, until the cheese is set and golden brown (homemade cheese) or melted (store-bought cheese).
3. Divide the soup into bowls and top each bowl with a slice of cheese toast. It would be nice if the slices of toast sank into the soup – it’s the most delicious way to enjoy bread here!
4. The soup can be stored in the refrigerator in an airtight container for up to a week and frozen for up to 6 weeks.