Indulge in Vegetarian French onion soup’s rich, savory flavors! Caramelized onions, sherry, crusty bread, and melted gouda cheese make this version irresistible.
This is the best French onion soup I’ve ever eaten, and it doesn’t involve a stock base. Instead, the onions are slow-cooked to develop the utmost flavor before water, and a few other additions go into the pot to help form a rich onion-broth-based soup, and the result is AMAZING! It’s warm, comforting, and simple to put together. It has a longer cooking time (four hours, to be exact), but you only need to watch the soup for about 30 minutes. Because of that, I feel good telling you that this soup is a totally doable weekday dinner, especially if you plan ahead.
Why You’ll Love This French Onion Soup
- Requires less than 10 ingredients – Aside from having to go out and buy a few bags of onions, you likely have everything you need for this soup in your kitchen right now.
- Lengthy cook time – You’re probably wondering how this is a plus, right? Well, only 30 minutes is active, so you can go about your day and have French onion soup ready and waiting. Moreover, a low, slow cook means more profound, decadent flavors.
- Cheesy French bread topping – French bread topped with melted gouda adds texture, flavor and soaks up the soup broth while enhancing presentation.
- Vegetarian – I replaced the traditional beef broth with this delicious onion, vinegar, sherry broth.
Vegetarian French Onion Soup Ingredients
- Onions: Traditionally, French onion soup is made with sliced yellow onions. They caramelize nicely, hold up well when cooked, and have a lovely sweetness.
- Butter: Unsalted butter is the best fat to sauté onions because it helps kickstart a delicious soup base.
- Water: Water is the only liquid used in this soup recipe. No broth is required!
- Sherry: The fortified wine brightens the flavor of broth-based soups. With that brightness comes a sweet nuttiness that lends itself well here.
- Gouda Cheese: Use a younger gouda to top French onion soup. It melts beautifully.
(Scroll down to the bottom for the printable recipe card with exact measurements and instructions.)
How to Make French Onion Soup
French onion soup is easy to make but requires a few hours to cook. To make it:
- Sauté the onions: Add the butter and onions to a stock pot and sauté over medium-high heat. During this time, the onions will start to cook down and become translucent.
- Continue to cook low and slow: Reduce the temperature to medium-low and leave the onions to cook down and caramelize.
- Time to make the broth: Now that the onions have developed tons of flavor, in goes the water, sherry, and vinegar (to give the soup a little zing). Once added, leave the soup to simmer. The caramelized onions meld with water to form an oniony soup broth during this time.
- Broil: Ladle the soup into bowls, top each serving with a slice of bread and grated gouda, then place under the broiler until melted, bubbly, and golden brown.
Variations, Substitutions & Cooking Tips
- Make it vegan – Swap the butter for vegan butter (or refined coconut oil) and the gouda for a vegan substitute. If you’re not a fan of vegan cheeses, skip it altogether and finish each serving with a slice of bread. French baguettes are usually vegan, but checking is always a good idea.
- Adapt for a gluten-free diet – All you have to do is replace regular French bread with French bread made with gluten-free flour.
- Try another onion – Sweet onions yield a mellow, sweet soup, while red onions provide a deeper flavor with some noticeably bitter notes.
To make French onion soup ahead of time, follow the recipe as directed up to completing the actual soup; omit the bread and cheese. Bread and cheese should go on right before serving; otherwise, you’ll have a soggy, cheesy mess on your hands. Alternatively, you can caramelize the onions in advance, store them in an airtight container for up to 3 days, and put the soup together when mealtime rolls around. The choice is yours!
Storage and Freezer Tips
Store the soup in an airtight container for up to 4 days. Before storing, do not let the soup sit at room temperature for more than 2 hours. If you wish to keep French onion soup longer than 4 days, freeze it. To freeze, allow the soup to cool, transfer it to freezer bags, date and label the bags, and freeze flat to save space.
How to Reheat
Reheating French onion soup is relatively simple. If frozen, thaw the soup before using one of the steps below. Here are a few methods:
- Stovetop method: Transfer the soup from the container to a saucepan and place it over medium heat. Occasionally stir as the soup heats up for 10-12 minutes or until the soup is heated through.
- Microwave method: Heat French onion soup in a microwave-safe bowl for 30-second intervals, stirring after each interval until the soup is heated.
- Oven method: Transfer the soup to an oven-safe container and cover it with foil. Place in a preheated oven set to 350°F and heat the soup for 15-20 minutes or until it’s warm.
- 6-8 lbs. yellow onion
- 1 tbs. butter (to make this vegan, simply use earth balance)
- 6 cups water
- ¼ cup cooking sherry
- 1 tbs. white wine vinegar
- To Serve
- 1 French baguette
- 1 cup freshly grated Gouda
- In a large stock pot, add the butter and sliced onions and place over a medium-high heat for about 30 minutes (the onions should be translucent and begin releasing their water at this point).
- Then, reduce the temperature to medium-low and cook for about 3 hours or until caramelized, stirring occasionally.
- Add the water, sherry, and vinegar and let cook for another 30 minutes.
- Preheat the oven to Broil. Line a baking sheet with parchment paper and lay out slices of French bread and top with the grated cheese. Cook for just about a minute, or until the cheese has melted and starts turning golden brown.
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