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Vegan French Onion Soup

Vegan French Onion Soup

The vegan mozzarella cheese sauce and homemade croutons that top this French onion soup create a trifecta of flavor. It's as good as you want it to be. It's a bit labor intensive. And worth it. You can skip the homemade croutons if you have good bread.
Prep Time 10 mins
Cook Time 45 mins
Total Time 55 mins
Course Main Dish
Servings 6


French onion soup

  • 4 large yellow onions
  • 8 cups vegetable broth
  • 2 cups water
  • 2 Tbsp. soy sauce of choice
  • 1/4 cup nutritional yeast flakes
  • 1 Tbsp. white wine vinegar substitute balsamic
  • 1 Tbsp. thyme
  • 1 tsp. garlic powder
  • 1 tsp. white pepper or black
  • 1/2 tsp. smoked paprika
  • 1 large bay leaf

Vegan Mozzarella Cheese Sauce

  • 1/2 cup cashews presoaked
  • 1 cup water
  • 3 Tbsp. arrowroot flour
  • 2 Tbsp. nutritional yeast flakes
  • 1/2 Tbsp. miso paste
  • 1/2 Tbsp. lemon juice
  • 1/2 tsp. tahini
  • 1/2 tsp. onion granules
  • 1/2 tsp. garlic salt
  • 1/4 tsp. apple cider vinegar
  • 1/4 tsp. ume plum vinegar
  • 1/4 tsp. Italian seasoning

Homemade croutons

  • 5 slices bread
  • 2 Tbsp. balsamic vinegar
  • 1 Tbsp. water
  • 1/2 tsp. garlic salt
  • 1/2 tsp. onion powder
  • 1/2 tsp. rosemary
  • 1/4 tsp. smoked paprika


  • Cut onions in half, then into thin slices. Place in a soup pot and caramelize on high for about 30 minutes, adding splashes of water as needed to avoid sticking. Onions are done when they are deep brown and stringy.
  • Meanwhile, whisk the remaining ingredients into a large bowl. Set aside. Don't forget to stir the onions regularly!
  • Place all of the ingredients for the vegan mozzarella cheese sauce into a high speed blender. Yes, there are a lot of them. And the end result is worth it. But don't worry if you are missing something. Use what you have, taste at the end, and adjust as needed.
  • Don't forget to keep stirring the onions. Blend the vegan mozzarella cheese sauce ingredients for at least 10 minutes. At some point, you will see steam--that's the blender cooking for you! Keep blending until you hear the motor starting to work harder. The sauce is thickening. Give it a few more minutes.
  • Once the onions are caramelized, pour the seasoned vegetable broth mixture into the pot. Bring to a boil, reduce heat to low and simmer for 15 minutes. Remove bay leaves.
  • Unless you have awesome sourdough bread and prefer to serve thin slices topped with the cheese sauce in the soup, make the homemade croutons (What's another few minutes of effort?) Preheat the oven to 400 degrees. Rip your favorite bread into small pieces and place in a bowl. Whisk together the rest of the ingredients and pour over the bread, stirring to thoroughly coat. Line a baking sheet with parchment paper and bake croutons for 15 minutes, stirring periodically.
  • Bon appetite! Serve soup in bowls and top with croutons and cheese sauce. If you want to get fancy, place under a broiler for a few minutes to get the cheese sauce bubbly and bread or croutons extra crispy.


As this recipe has a lot of ingredients and takes a lot of time, consider doubling it. Delicious leftovers are so convenient, and you can freeze it. The cheese sauce can be used in another meal (or eaten solo) . . .