Easy vegan French onion soup with caramelized onion, garlic, & thyme in rich veg broth, topped with ‘cheesy’ baguette for a tasty, sophisticated starter or side!
Why You’ll Love This Recipe
French onion soup is an iconic, nostalgic dish, and it turns out it’s actually so easy to make this sophisticated-looking soup entirely dairy-free with only a few simple ingredient swaps.
The resulting vegan French onion soup is rich and savory, made with caramelized onions, rich vegetable broth, aromatic garlic, fresh thyme, and several other simple, budget-friendly ingredients, topped with crusty bread and bubbly vegan cheese.
It’s super cozy, comforting, and satisfying – perfect for cooler months, dinner parties, special occasions, and when you crave comfort. Plus, despite its richness, vegan onion soup is also nourishing, boasting several vitamins and minerals (Vitamin C, B6, potassium, and folate), antioxidants, and prebiotics!
Looking for more nostalgic vegan meals? Try vegan American goulash, vegan chicken and dumplings, and one-pot vegan hamburger helper.
The Ingredients
Refer to the recipe card for the full list of ingredients, substitutes, and quantities.
Recipe Variations
- French onion leek soup: For a milder onion flavor and sweetness, replace a portion of onion with leek.
- Sugar: Enhance the caramelized sweetness with a pinch of sugar.
- Miso paste: A teaspoon of sweet white miso adds complex, umami-rich depth.
- Bay leaves: Add 2 for a more complex savory flavor. Remove before serving.
- Mushrooms: For rich, umami flavor in this vegan French onion soup recipe.
- Nutritional yeast: Add just a little for nutty, 'cheesy' flavor with umami.
- Pulses: For protein, fiber, and heartiness – add a can of green/brown lentils or cannellini beans.
How to Make Vegan French Onion Soup
Step 1: Use a sharp knife, mandoline, or food processor slicing disk to thinly slice the onions (about ¼-inch). Meanwhile, melt the vegan butter in a large saucepan over medium heat.
Step 2: Add the onions to the pan, stir, cover, and reduce the heat to medium-low. Cook for 10 minutes, stirring regularly. If the pan gets dry, add a splash of water.
10 minutes is the absolute minimum for good flavor. However, for a deeper, richer flavor, caramelize the onions fully (45-60 minutes, stirring often).
Step 3: Add the water, bouillon, vinegar, vegan Worcestershire sauce, thyme, salt, and pepper.
Step 4: Mix well, cover again, and bring to a boil over medium-high. Immediately lower to a simmer and cook for 30 minutes. Remove the lid and set aside. Meanwhile, preheat a broiler for 5 minutes.
Step 5: Ladle the soup into oven-safe bowls over an oven tray. Top each with a slice (or two) of bread, a slice of vegan provolone, and a tablespoon of vegan parmesan.
Step 6: Transfer the baking sheet to the top of the oven, broiling for 2-3 minutes until the vegan cheese is bubbly. Finally, garnish the dairy-free French onion soup with black pepper and serve!
FAQs
Yellow onions are ideal for tasty French onion soup, due to their well-balanced flavor and higher natural sugar content, perfect for deep, rich caramelization.
Alternatively, sweet onions offer an even sweeter flavor. White onion is milder and more robust. Red onion is a little more bitter. Use a blend for depth.
Use sturdy bread that won’t immediately fall apart in the soup. Many prefer French baguette, though sourdough (which adds tang) or another rustic loaf will work. Toast it to further reduce the chance of sogginess.
Prepare the soup, minus the vegan cheesy bread topping, up to 2 days in advance, then reheat, assemble, and broil when wanted.
Pro Recipe Tips
- Quick prep: Use a mandoline to slice the onion in no time at all.
- For the deepest, richest flavor: 10 minutes is the minimum for a flavorful homemade onion soup. If you have the time, I highly recommend caramelizing the onions for 45-60 minutes until soft, sweet, and richly golden-brown.
- For thicker soup: Either add 2-3 tablespoon flour to the onions before step 3 and cook for 2 mins before continuing OR add cornstarch (in a slurry) towards the end, increasing the heat and stirring until thickened.
- To avoid soggy bread: Lightly toast it before adding it to the soup.
Serving Suggestions
- A leafy side salad – Vegan Caesar salad or spinach/kale/arugula salad.
- Veggie salad – vegan cobb salad, carrot salad, etc.
- Roasted veggies– Like broccoli or mixed garlic herb roasted veggies, air fryer asparagus, etc.
Can You Freeze French Onion Soup?
Store the vegan/vegetarian French onion soup leftovers, minus the bread topping, in an airtight container/Ziplock/Stasher in the fridge for 3-4 days OR in the freezer for up to 3 months.
Thaw in the refrigerator overnight before reheating on the stove or in a microwave (in 30-second increments) until warm. Then, add the bread and vegan cheese and broil.
Vegan French Onion Soup
Ingredients
- 4 large yellow onions
- ½ cup unsalted plant-based butter
- 5 cups water
- 3 vegetable bouillon cubes
- 3 tablespoons sherry vinegar
- 1 tablespoon of vegan Worcestershire sauce
- 1 teaspoon dried thyme
- ½ teaspoon of salt
- 1 teaspoon of black pepper
- 1 baguette or one loaf of French bread, sliced
- 6 slices vegan provolone cheese
- 6 tablespoons of grated vegan parmesan cheese
Instructions
- Using a mandoline, slice the onions very thinly. Set them aside on a cutting board. You could also use a knife to slice the onions as thinly as possible.
- In a large pot with a lid over medium heat, melt the vegan butter and wait 1 minute for it to get hot.
- Add the onions, stir, cover, reduce the heat to a medium-low, and cook for 10 minutes. Stir regularly to prevent burning. The onions will release some water. If they don't and they’re beginning to brown, add a splash of water. This process will soften and slightly caramelize the onions. Once the 10 minutes have passed, add the water, bouillon cubes, sherry vinegar, vegan Worchester sauce, thyme, salt, and pepper. Mix well, cover with the lid, turn up the heat to a medium-high, and bring to a boil. Once it begins to boil, turn the heat down to a simmer and cook for 30 minutes.
- Once the 30 minutes have passed, remove the lid, stir, and set aside in the pot.
- Set your oven to broil and preheat it for 5 minutes.
- Carefully ladle the soup into individual oven-safe bowls, add a slice of bread, top it with a slice of vegan provolone, and one tablespoon of vegan parmesan. To make it easier, place the bowl on a cooking sheet and place it on the top rack of the oven. Broil for 1 minute and check how fast the vegan cheese is melting. Broil for 2 minutes or until the vegan provolone has melted.
- Carefully remove the baking sheet with the bowls and set them on a cooling rack.
- Garnish with some black pepper and serve immediately.
Notes
- Quick prep: Use a mandoline to slice the onion in no time at all.
- For the deepest, richest flavor: 10 minutes is the minimum for a flavorful homemade onion soup. If you have the time, I highly recommend caramelizing the onions for 45-60 minutes until soft, sweet, and richly golden-brown.
- For thicker soup: Either add 2-3 tablespoon flour to the onions before step 3 and cook for 2 mins before continuing, OR add cornstarch (in a slurry) towards the end, increasing the heat and stirring until thickened.
- To avoid soggy bread: Lightly toast it before adding it to the soup.
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Andrea says
Love how this soup turns out!