The Best Vegan French Onion Soup (You Won’t Believe It’s Dairy-Free)

Is there anything more comforting than a steaming bowl of French Onion Soup? That intensely savory broth, the mountain of sweet, jammy onions, and that irresistible cap of crusty, cheesy bread.

For years, this classic bistro staple felt out of reach. Traditional recipes rely heavily on beef broth and Gruyère cheese, leaving a plant-based version seeming like a pale imitation.

But I’m here to tell you that’s simply not true. After countless hours of testing, I’ve perfected a recipe that doesn’t just mimic the original; it stands proudly on its own.

We’ll unlock the secrets to developing a deep, umami-rich broth and a mind-blowingly stretchy, gooey vegan cheese that will make you fall in love with this soup all over again.

What Ingredients Do I Need?

To create a truly spectacular soup, you need the right building blocks. Each ingredient plays a critical role in layering flavor to replicate the complexity of the classic dish. Here’s what you’ll need and why it matters.

• Onions: The undisputed star. Yellow onions are the best choice. They strike the perfect balance between sweetness and a slight, savory bite when caramelized. Sweet onions like Vidalia can make the final soup overly sweet, while red onions can alter the color and add a sharper flavor. You’ll need about 6 large ones, which seems like a lot, but they cook down dramatically.
• Fat: Use a good quality olive oil or a neutral vegan butter. This is for slowly coaxing the sweetness out of the onions during caramelization.
• Dry White Wine: This is non-negotiable for authentic flavor. It deglazes the pan, lifting all those flavorful browned bits (the “fond”) into the soup, and adds a crucial layer of acidity and brightness. A Sauvignon Blanc or Pinot Grigio works wonderfully. Always use a wine you’d be happy to drink! If you’re unsure if your wine is vegan, resources like Barnivore can help.
• Vegetable Broth: Choose a high-quality, flavorful vegetable broth. A mushroom or umami-rich broth will add even more depth, beautifully mimicking the richness of traditional beef broth.
• Herbs: Fresh thyme and a bay leaf are classic choices that infuse the broth with an earthy, aromatic quality. If you’re interested in growing your own fresh herbs, thyme is a fantastic place to start.
• Baguette: A day-old, crusty baguette is perfect. It’s sturdy enough to hold up to the soup without turning to mush instantly.
• For the Stretchy Vegan Cheese: This simple blend of raw cashews, water, lemon juice, salt, and tapioca starch creates a magical, mozzarella-like topping. The tapioca starch is the secret to that signature gooey stretch.
• Nut-Free Cheese Option: For those with nut allergies, you can achieve a similar result by blending 1 cup of boiled potatoes and carrots (mostly potato) with 2-3 tablespoons of olive oil, 1/4 cup nutritional yeast, 1 teaspoon salt, and 4 tablespoons of tapioca starch until smooth.

Step 1: Master the Art of Caramelizing Onions

This is where the magic happens, and patience is your most important ingredient. Rushing this step is the single biggest mistake you can make.

Proper caramelization is a slow process of breaking down the sugars within the onions, resulting in a deep, sweet, and incredibly complex flavor. This process is a combination of caramelization (browning of sugar) and the Maillard reaction, a chemical reaction between amino acids and reducing sugars as explained by food scientists.

First, slice your onions thinly and consistently. Uniform slices ensure they all cook at the same rate.

Heat the olive oil in a large, heavy-bottomed pot or Dutch oven over medium heat. Add the massive pile of onions and a pinch of salt.

The salt helps draw out moisture, preventing the onions from burning too quickly. Cook, stirring occasionally, for about 15-20 minutes until the onions have softened significantly and released their water.

Now, reduce the heat to medium-low and continue to cook for another 30-45 minutes. Stir every 5-10 minutes, scraping the bottom of the pot.

You’ll see them transform from pale white to a light golden, then a copper brown, and finally to a deep, rich, jam-like mahogany. This is the color that equals flavor.

Don’t be tempted to crank up the heat to speed it up; you’ll end up with burnt, bitter onions instead of sweet, caramelized ones.

Step 2: Build a Deep and Savory Broth

Once your onions have reached that perfect deep brown, it’s time to build the soul of the soup. Add your minced garlic and cook for just a minute until fragrant.

Then, sprinkle the flour over the onions and stir to combine. This is your thickener (a roux) which will give the broth a lovely, velvety body.

Let it cook for another minute to remove any raw flour taste. Now, turn the heat up slightly and pour in the white wine.

This is the deglazing step. As the wine sizzles, use a wooden spoon to scrape up every last browned bit from the bottom of the pot.

This fond is pure, concentrated flavor, and incorporating it is absolutely essential. Let the wine cook for a few minutes until the strong alcohol smell has dissipated and it has reduced by about half.

Finally, pour in the vegetable broth, add the fresh thyme leaves and the bay leaf, and season with black pepper. Stir everything together, bring it to a boil, then reduce the heat to a gentle simmer.

Let the soup simmer for at least 15-20 minutes, allowing all the flavors to meld into a harmonious, savory broth. Remove the bay leaf before serving.

Step 3: Create the Perfect Stretchy Vegan Cheese

While the soup is simmering, you can prepare the topping that takes this recipe over the top. Traditional French onion soup uses Gruyère, which is known for its melting and stretching capabilities.

We can replicate this beautifully with a simple homemade vegan cheese. Mastering homemade vegan staples like this is a game-changer. Start by soaking your raw cashews in boiling water for at least 5 minutes.

This softens them up, ensuring a silky-smooth cheese sauce. Drain the cashews and add them to a high-speed blender.

Add the fresh water, lemon juice, salt, and the all-important tapioca starch. Blend on high for 1-2 minutes, or until the mixture is completely smooth and free of any grit.

Pour the liquid into a small saucepan and heat over medium-high heat. Now, you must stir constantly with a whisk or spatula.

The mixture will start to thicken very quickly. Keep stirring, and within a few minutes, it will transform from a milky liquid into a thick, stretchy, gooey mass that pulls away from the sides of the pot.

As soon as it reaches this texture, remove it from the heat immediately to prevent it from becoming rubbery. You’ll be amazed at the texture!

Step 4: Assemble and Broil to Golden Perfection

The grand finale! It’s time to bring all the elements together for that classic, bubbly finish.

First, preheat your oven’s broiler and arrange your baguette slices on a baking sheet. Toast them for 5-7 minutes, or until they are lightly golden and crisp.

Now, you have two options for assembly. For the classic bistro experience, ladle the soup into oven-safe bowls.

Top each bowl with one or two slices of the toasted baguette. Spoon a generous amount of the stretchy vegan cheese over the bread.

Place the bowls on a sturdy baking sheet and carefully slide them under the broiler. Broil for 2-4 minutes, watching them like a hawk, until the cheese is bubbly and develops beautiful golden-brown spots.

If you don’t have oven-safe bowls, no problem! Simply spoon the cheese onto the toasted baguette slices on your baking sheet.

Place the sheet under the broiler until the cheese is bubbly and browned. Ladle the hot soup into your regular bowls and gently place one or two of the cheesy toasts on top.

The result is just as delicious!

Pro Tips for the Best Results

Taking your soup from ‘great’ to ‘unforgettable’ often comes down to a few small details and techniques. Having made this recipe countless times, I’ve gathered some tips that will ensure you get restaurant-quality results every single time.

• Slice Onions Pole-to-Pole: For the best texture, slice your onions from the root to the stem (pole-to-pole) rather than across the middle. This cuts with the grain of the onion fibers, helping them hold their shape better during the long cooking process.
• Don’t Fear the Brown Bits: Those dark, sticky spots that form on the bottom of the pot during caramelization are called the ‘fond’, and they are a goldmine of flavor. Don’t mistake them for burn. As long as they aren’t black and acrid, they are your friend. The wine will lift them right off the bottom and into your soup.
• Use Room Temperature Broth: Adding cold broth to the hot pot can cause a drastic temperature change. While not a disaster, using room temperature or slightly warmed broth helps maintain a consistent cooking temperature and allows the flavors to meld more seamlessly.
• Balance the Flavors: After your soup has simmered, give it a taste. Does it need a little more brightness? A tiny splash of apple cider vinegar or extra lemon juice can wake up all the flavors. Is it missing a certain depth? A teaspoon of vegan Worcestershire sauce or a touch of balsamic vinegar can add a wonderful new dimension.
• Get the Best ‘Melt’: For an extra-browned, bubbly top, you can use a small kitchen torch to finish the cheese after broiling. This gives you precise control over the browning without the risk of overcooking the soup.

How to Store, Freeze, and Reheat Your Soup

This soup is a fantastic make-ahead meal, perfect for meal prep or for saving leftovers. Here’s how to store and reheat it properly to maintain its deliciousness.

• Refrigerating: You can store the soup base (without the bread and cheese) in an airtight container in the refrigerator for up to 5 days. The flavors will actually deepen and become even more complex overnight! The prepared vegan cheese can also be stored in a separate airtight container in the fridge for the same amount of time. When you’re ready to serve, simply reheat the soup on the stovetop until hot, and then prepare the cheesy toast and broil as directed.
• Freezing: This soup freezes beautifully! Allow the soup base to cool completely, then pour it into freezer-safe containers or resealable bags. It will keep well in the freezer for up to 3 months. I recommend freezing it in individual portions for quick and easy meals.
• Reheating from Frozen: The best way to reheat is to let the soup thaw overnight in the refrigerator. Then, gently warm it in a saucepan over medium heat. You can also reheat it from frozen in a pot over low heat, stirring occasionally until it’s fully thawed and hot. Once reheated, assemble with freshly toasted bread and your cheese topping for the best texture. I do not recommend freezing the cheesy toast, as the bread will become soggy upon thawing.

Conclusion

There you have it—a bowl of Vegan French Onion Soup that sacrifices none of the soul-warming, decadent flavor of the original. By patiently caramelizing the onions and building layers of flavor, you’ve created something truly special.

This recipe is more than just a meal; it’s a comforting ritual that proves compassionate cooking can be the most delicious of all. It joins the ranks of other beloved comfort foods that shine in a plant-based form, like our ultimate vegan baked beans recipe. I hope this becomes a cherished recipe in your home for years to come.

Happy cooking!