Rich, sweet, and savory, this vegetarian French Onion Soup is a revelation in a bowl. I’ve unlocked the secret to making the absolute best bowl of onion soup using healthy, homemade veggie stock and the traditional crunchy, cheesy crouton topping, and I can’t wait to share it with you!
About this recipe
I have received so many requests for this classic French soup over the years. In fact, it is one of the most requested recipes of all time! It’s really no surprise though. French Onion Soup is a tongue-titillating meal that is a lovely balance of savory and sweet flavors and gorgeous textures. It’s also super cozy and budget-friendly!
French Onion Soup is made by caramelizing onions in butter (yum) which are then deglazed with dry white wine and further cooked with meat or veggie stock (double yum), then finished with toasted bread or croutons with melted cheese (TRIPLE YUM!).
I make this vegetarian version of French Onion Soup with good homemade vegetable stock. The stock is an essential ingredient that can make or break your soup. I suggest using either homemade stock (which is the best option) or a low sodium stock (which is an acceptable alternative).
The most important technique to get this dish right is caramelizing the onions. While this step isn’t difficult, it’ll take about 40 to 45 minutes depending on the pan thickness and size. Go slow and steady when sautéing the onions to ensure you coax the most marvelous flavor from them.
In this post, I offer the option to broil (grill) or toast bread separately. Most often, I place the toasted bread topped with cheese on the soup and broil it in the oven till the cheese melts. You can also bake cheese toasts separately and then place them on the soup while serving. Choose whatever is easiest for you.
Ingredients & Substitutions
Perhaps surprisingly, this complexly flavored soup has just 10 simple ingredients. Here’s what you’ll need:
- Onions – Any variety of onions can be added like red, yellow, white onions, shallots or even leeks. Depending on the type of onions used, the flavors will vary. I prefer this soup with red onions. Just make sure to slice the onions evenly so that they get cooked uniformly.
- Butter – Add either salted or unsalted butter. Make sure to adjust the seasoning as you go. Vegan butter can also be added, if needed.
- Dry White Wine – Wine gives a lovely depth of flavor here, but you can sub in apple cider vinegar, white wine vinegar, red wine vinegar, or sherry if needed.
- Flour – Either whole wheat flour or all-purpose flour can be used. A cup-for-cup all-purpose gluten-free flour blend can also be used, if needed.
- Bay Leaf – Tej Patta (Indian bay leaf) can also be used.
- Garlic – Fresh cloves are preferred for a more potent flavor, but you can use 1/4 teaspoon of ground garlic powder for each clove if necessary.
- Vegetable Stock – If possible, I recommend using a flavorful homemade stock. If not, opt for a low-sodium, high-quality store-bought brand.
- Salt & Freshly Crushed Black Pepper – Simple seasonings yield delicious results.
- Fresh Rosemary or Thyme – Optional, but recommended for depth of flavor. 1 teaspoon of dried herbs can also be used as an alternative to fresh herbs.
- Crusty Bread – French bread, baguette, sourdough, or sandwich bread will all work.
- Gruyere Cheese – Opt for a vegetarian (rennet-free) version. While Gruyere is the classic choice for this French soup, you can also swap in Swiss cheese, provolone, fontina, gouda, mozzarella or parmesan as needed. Feel free to use plant-based cheese for a vegan option.
Step-by-Step Guide
How to make French Onion Soup
Preparation
1. Peel, rinse and thinly slice about 4 medium-sized onions (300 grams) for a total of 3 cups of thinly sliced onions. Sometimes there are some black spots or marks on the onions and these need to be completely rinsed before slicing the onions. Finely chop or mince two small to medium-sized garlic cloves and keep aside.
Pro Tip: Do onions make you cry? Try freezing them for about 15 minutes before slicing to inhibit the development of the sulfurous compound that causes eye irritation.
Caramelize onions
2. Place a heavy-bottomed pot on the stovetop. Add 3 tablespoons butter and let the butter melt.
3. When the butter starts melting, add the sliced onions.
4. Mix the onions with the butter really well.
5. Add a pinch of salt and stir.
6. Stirring often, continue to sauté the onions on a low or medium-low flame.
7. First, the onions will become translucent. Continue to stir at intervals of 2 to 3 minutes.
8. After some minutes the onions will start to become light golden.
9. The onions need to be cooked more to reach their full caramelized potential. After the onions reach a light golden stage, they have to be stirred continuously so that they are evenly cooked and become a deep golden brown.
Deglaze
10. When the onions have caramelized and have a nice golden color to them, add 2 tablespoons dry white wine. If you do not have white wine, then add ½ to 1 tablespoon apple cider vinegar, white wine vinegar, red wine vinegar, or sherry.
11. Deglaze and scrape, remove all the stuck bits of browned onions from the bottom. Sauté for 1 to 2 minutes on a low to medium-low flame.
Add flour
12. Add 2 tablespoons of whole wheat flour or all-purpose flour.
13. Mix very well and sauté for 2 minutes on a low to medium-low flame.
14. Add ½ teaspoon finely chopped garlic and 1 bay leaf. Stir and sauté for a minute. If the onions start sticking to the pan, then sprinkle in some water or stock.
15. Add 3.5 cups of vegetable stock.
16. Place 1 sprig of rosemary or thyme on the stock.
Simmer French Onion Soup
17. Season with salt to taste. Remember that as the soup simmers, the flavors will become more concentrated, so start with a small amount of salt to begin.
18. Add ¼ to ½ teaspoon freshly crushed black pepper. Mix again.
19. Cover the pan. Simmer for 30 minutes on a low flame. You can check the soup and give it a quick stir after about 10 to 15 minutes.
20. In this below photo, the French Onion Soup is done and ready to be served.
Toast bread, then choose option 1 or 2
21. When the soup is simmering, toast the bread.
22. Place the bread slices on a baking tray. Brush with some melted butter or olive oil.
23. Preheat the oven for 15 minutes at 230 degrees Celsius (450 Fahrenheit). In a preheated oven, toast the slices. Halfway through remove the tray and turn each slice.
24. Remove and keep aside when the slices become light golden or lightly toasted.
Option 1: Broiling (Grilling)
25. Now you can use baking safe soup bowls for individual servings or use a baking safe pot or pan. Pour the soup in these bowls. If you have used a Dutch oven for making the soup, then you can place the croutons or toasted bread slices directly in it.
26. Place toasted bread slices on the onion soup.
27. Sprinkle grated vegetarian gruyere cheese all over the toasted bread slices.
28. Place the bowls on a baking tray, then broil in the already preheated oven at 230 degrees Celsius till the cheese melts. (Broiling means placing the pan or tray beneath the top heating element of the oven.)
29. Let cheese melt or become golden. Remove and serve hot. You can garnish with some chives or parsley while serving.
Option 2: Baking cheese toasts separately
30. For baking the cheese toasts separately , sprinkle grated gruyere cheese (vegetarian) on the toasted bread slices.
31. Bake at 230 degrees Celsius in a preheated oven till the cheese melts. Keep the tray near the top heating element so that the cheese melts quickly.
32. Bake till the cheese melts.
33. Pour steaming hot French Onion Soup in soup bowls. Place the cheese toasts on the onion soup. Garnish with some parsley or chives while serving.
Serve hot French Onion Soup as a starter or as a light dinner meal.
Expert Tips
- Herbs: You can skip adding fresh herbs like rosemary or parsley if you don’t have them. Fresh thyme can also be added instead of rosemary.
- Vegetable Stock: Avoid using packaged stock having a high sodium content. It is better to make vegetable stock and use it in the recipe.
- Flour: You can use either whole wheat flour or all-purpose flour. Gluten-free flour is also an alternative.
- Caramelizing Onions: For a truly authentic French onion flavor, it is important to caramelize the onions really well. So, use a heavy pan or pot, keep it on a low or low-medium flame, and stir often when sautéing the onions. Toward the end stage when the onions become light golden, you have to stir often so that the onions get an even golden color and do not burn or darken. Even a slight burning of the onions will ruin the entire batch.
- Wine: Sherry wine, dry white wine or red wine can be used. If you do not plan to add wine, then use ½ to 1 tablespoon of either of these vinegars – white wine vinegar, red wine vinegar or apple cider vinegar.
- Gluten-Free Option: For the bread, use a gluten-free bread like a rice flour bread and swap in a gluten-free flour blend to help thicken the soup.
FAQs
Oops! sounds like you made the mistake of cooking the onions too hot too fast. Make sure you use a heavy-bottomed pot to prevent scorching, keep the onions on a low flame, and stir often. Don’t rush! The whole process will take about 40-45 minutes if you do it properly.
Pro Tip: Make an extra large batch of caramelized onions, then freeze the extras for later. They’re delightful flavor bombs that can be used in a multitude of recipes, and they’ll keep well in the freezer for up to 4 months!
Sure! Just opt for either EVOO or plant-based butter. Also, use vegan cheese.
Sure! Just use gluten-free bread and gluten-free flour.
I like to remove the root and stem ends, slice the onions in half vertically (from pole to pole), then make thin vertical slices on each half.
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French Onion Soup
Our favorite French Onion Soup made vegetarian with the classic recipe.
Prep Time 5 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 20 minutes
Preparation
Cooking onions
Place a heavy pan on the stovetop. Add butter.
When butter states melting, add the sliced onions with a pinch of salt.
Mix the onions with the butter really well.
Stirring often continue to sauté the onions on a low or medium-low flame till the onions caramelize.
Initially stir the onions after an interval of 2 to 3 minutes till they become light golden. When the onions turn light golden, then stir the onions continuously for even cooking and browning.
Deglazing
Once the onions have caramelized and have a nice golden color to them, add 2 tablespoons dry white wine.
Deglaze and remove all the stuck bits of caramelized onions from the bottom of the pan. Sauté for 1 to 2 minutes.
Adding flour
Now add flour. Mix very well and sauté for 2 minutes.
Then add the garlic and bay leaf. Mix well and sauté for a minute. If the onions start sticking to the pan, then sprinkle some water or stock.
Add the vegetable stock, 1 rosemary sprig. Also, season with salt and freshly crushed black pepper. stir and mix.
Salt is added as the veggie stock I had made, did not have any salt. If using stock with salt in it, then you can skip adding salt or add less of it.
Cooking soup
Toasting Bread or Baguette slices
When the soup is simmering, toast the slices of french bread or baguette or regular wheat bread or white bread. Slice the french bread.
Place the baguette slices on a baking tray. Brush with some melted butter or olive oil.
In a preheated oven toast bread slices at 230 degrees Celsius (450 degrees Fahrenheit) till light golden.
Broiling (Grilling)
Pour soup in a baking safe soup bowls for individual servings or use a baking safe pot or pan.
Place toasted bread slices on the onion soup.
Sprinkle grated gruyere cheese all over the toasted bread slices.
Place the bowls in a baking tray. Keep the tray in a preheated oven and broil at 230 degrees Celsius (450 degrees Fahrenheit) till the cheese melts. Broiling means keeping the pan or tray beneath the top heating element of the oven. The top heating element should be used when baking.
Let cheese melt or become golden. Remove and serve hot garnished with some parsley or chives.
Baking Cheese toasts separately
For baking the cheese toasts separately top grated gruyere cheese on the toasted baguette slices.
Bake at 230 degrees Celsius (450 degrees Fahrenheit) in a preheated oven till the cheese melts.
Place the cheese toasts on the soup.
Serve hot. Garnish with some parsley or chives while serving.
- Herbs: Herbs like rosemary or parsley can be skipped completely. Fresh thyme can also be added instead of rosemary.
- Onions: Slice the onions thinly and evenly. You can use any variety of onions like red onions, white onions, yellow onions or shallots.
- Vegetable stock: Avoid using packaged stock having a high sodium content. It is better to make vegetable stock and use it in the recipe.
- Flour: You can either whole wheat flour or all-purpose flour.
- On caramelizing onions: For the soup to have a truly authentic and great flavor, it is important to caramelize the onions really well. So use a heavy pan or pot. Stir often when sauteing the onions. Toward the end stage when the onions become light golden, you have to stir often so that the onions get an even golden color and do not burn or darken. So stirring and cooking onions on a low to medium-low flame is the key. Even a slight burning of the onions will ruin the entire soup.
- Wine: You can use sherry wine or dry white wine. You can even use red wine. If you do not plan to add wine, then use vinegar. I suggest ½ to 1 tablespoon (depending on your taste) of white wine vinegar, red wine vinegar or apple cider vinegar.
- Gluten-free option: For the bread, use a gluten-free bread.
- Cheese: Apart from Gruyere cheese, you can also add a vegetarian Parmesan cheese.
- Vegan option: Replace with a vegan butter or olive oil or neutral flavored oil and vegan cheese.
Nutrition Facts
French Onion Soup
Amount Per Serving
Calories 519 Calories from Fat 198
% Daily Value*
Fat 22g34%
Saturated Fat 13g81%
Cholesterol 63mg21%
Sodium 1645mg72%
Potassium 360mg10%
Carbohydrates 60g20%
Fiber 5g21%
Sugar 11g12%
Protein 19g38%
Vitamin A 1214IU24%
Vitamin B1 (Thiamine) 1mg67%
Vitamin B2 (Riboflavin) 1mg59%
Vitamin B3 (Niacin) 4mg20%
Vitamin B6 1mg50%
Vitamin B12 1µg17%
Vitamin C 12mg15%
Vitamin D 1µg7%
Vitamin E 1mg7%
Vitamin K 4µg4%
Calcium 368mg37%
Vitamin B9 (Folate) 134µg34%
Iron 3mg17%
Magnesium 52mg13%
Phosphorus 321mg32%
Zinc 2mg13%
* Percent Daily Values are based on a 2000 calorie diet.
This Vegetarian French Onion Soup recipe from the archives was first published in October 2020. It has been updated and republished in February 2024.
Source: Dassana’s Veg Recipes
