Vegan French Onion Soup

Vegan French Onion Soup features caramelized onions in a rich & savory thyme broth, served with a warm, crusty baguette and gooey cheese on top, for a cozy entree or starter soup!

When the weather turns cold, this is one of my favorite go-to recipes!

This vegan French onion soup is my plant-based take on the classic, and after making it many times over the years, it’s become a true favorite in our house.

The onions are caramelized until they’re sweet and golden, then simmered into a rich, savory broth that feels both comforting and elegant.

When you’re craving classic French onion soup but want a vegan version, this recipe is incredibly satisfying and full of flavor. It’s made with simple, real ingredients and has that same cozy, soul-warming quality.

I especially love serving it with a slice of my Fennel & Cannellini Flatbread or an extra slice of toasted Artisan Bread with a little vegan cheese melted on top. It turns the soup into a complete, hearty meal.

So without further ado, let’s get caramelizing!

Ingredients You’ll Need

What makes this vegan French onion soup special is the layering of flavors — starting with deeply caramelized onions and building from there. Here’s exactly what I use and why:

• Onions — Yellow or white onions are my favorite because they caramelize beautifully and develop a rich, sweet depth. Red onions work too, though they’ll give a slightly different (but still delicious) flavor.
• Vegan Butter — I highly recommend Miyoko’s Vegan Butter. It has clean ingredients and browns wonderfully, which adds to that signature French onion flavor.
• Dry Wine — Both white and red work well. I usually use red wine for a deeper, more robust flavor, while white wine gives a lighter, brighter taste. Use whatever you have open — it makes a noticeable difference in the final broth.
• Flour — This helps thicken the soup slightly. I’ve successfully used unbleached all-purpose, spelt, whole wheat, and 1-to-1 gluten-free blends. A touch of arrowroot also works if you want it gluten-free.
• Thyme + Bay Leaves — Fresh thyme is lovely, but dried works great too. The bay leaves add a subtle background aroma that really rounds out the soup.
• Vegetable Broth — I almost always use Better Than Bouillon Veg Paste (affiliate link) (about 1½ teaspoons dissolved in water), which lets me control the sodium. Use your favorite boxed brand – regular or low-sodium.
• Salt + Pepper — Season generously. The soup benefits from a generous amount of salt to bring out the caramelized onion’s sweetness.
• Baguette — A small or medium loaf, sliced. Day-old bread actually works best because it holds up better under the broth.
• Vegan Cheese — Traditional recipes use Gruyère, but I love Miyoko’s Vegan Mozzarella. It melts beautifully. You can also dollop my Vegan Ricotta on the toasted bread for a lighter, fresher take!

How To Make Vegan French Onion Soup

Making French onion soup isn’t the prettiest, thanks to its very brown finish. But here are a few of the steps with photos to reference while cooking.

Note, the full printable recipe is at the bottom of this post in the recipe card.

• Prep the onions. Cut the onions lengthwise, lay the cut sides on a flat surface, and trim the ends. Peel away the outer skin, the onion’s first thin layer. Place the onion at one end and slice it lengthwise into thin strips. You should end up with about 2 lbs. of sliced onions (about 8-9 cups).

• Caramelize the onions. Using a 4 or 5 qt. pot, heat vegan butter or olive oil over medium heat. Add the onions, thyme, bay leaves, and salt (or salt + pepper). Cook the onions over medium heat for 45 minutes to 1 hour, stirring frequently. When done, onions will soften and turn a deep golden brown, as shown above.
• Add the flour. Sprinkle in the flour, stirring to incorporate until there are no white streaks, and cook for about 1 minute.

• Add the wine. Pour in the vegan wine and continue to cook for 10 minutes, stirring occasionally, to reduce the wine.
• Add the vegetable broth. Lastly, add the broth and pepper, bring to a boil, reduce heat, and simmer, uncovered, for about 30 minutes.

• Get ready to serve. Enjoy the soup as is with crusty bread, or bake individual portions as is traditional.
• Assemble soup bowls. Ladle French onion soup into individual, oven-safe bowls. Add 1 or 2 slices of the baguette on top of the soup, a layer of cheese, and a sprig of thyme. Place bowls on a rimmed baking sheet, as shown above right.
• Bake or broil. Place in a preheated oven set to 350°F for about 20 minutes. Alternatively, place 5 or 6 inches away from the broiler for about 5 to 7 minutes. The bread should get crispy on the edges, and the cheese will melt and may turn golden and slightly charred.

And that’s it! This easy French Onion Soup takes about 1.5 hours to prepare, but it’s worth the time and effort!

How to Store + Reheat

This soup stores beautifully, making it excellent for meal prep.

• Refrigerator: Leftover soup will keep well in an airtight container for 5 to 6 days. The flavors actually get even better after a day or two as everything melds together.
• Freezer: This soup freezes wonderfully for 2 to 3 months. I always freeze it without the toasted bread and cheese on top. Let the soup cool completely, then portion it into multi-use freezer containers (affiliate link) or zip-top bags (I like to freeze individual servings for easy lunches). Leave a little headspace for expansion. Thaw overnight in the refrigerator before reheating.
• Reheating: I prefer warming it gently on the stovetop over medium-low heat, stirring occasionally, until hot. This helps preserve the rich flavor. You can also reheat it in the microwave in 60-second intervals, stirring well between each, until warmed through.

My Tip: When serving after reheating or thawing, always toast fresh bread with vegan cheese on top. The contrast of the hot soup with the crispy, melty cheesy toast makes it feel fresh again.

Serving Suggestions

Vegan French onion soup is wonderful on its own, but I’ve found a few pairings that take it to the next level:

• Salad: I love serving it with a fresh, crisp salad to balance the rich, deeply caramelized flavor of the soup. My go-to options are the Classic House Salad or French Lentil + Bitter Greens Salad. The peppery greens and bright vinaigrette cut through the sweetness of the onions beautifully.
• Bread: A good piece of bread for dipping is almost essential. I highly recommend the Cannellini + Fennel Flatbread (the fennel adds a lovely subtle sweetness) or a thick slice of my Artisan Bread. Toasted until golden and topped with a little vegan cheese, it turns into the perfect cheesy crouton experience.

My favorite way to serve it: A big bowl of soup with a slice of toasted bread melting with vegan cheese on top, plus a simple green salad on the side. It feels like a complete, restaurant-quality meal.

More Vegan Soup Recipes!

• Hearty Vegan Lentil Soup
• Vegan Mushroom Soup
• Vegan Cauliflower Soup
• Vegan Minestrone Soup
• A Very Good Split Pea Soup

If you try this onion soup recipe, please let me know! Leave a comment and rate it below. I love to hear what you think, or any changes you make.

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