Easy No Crock Vegetarian French Onion Soup Recipe

French onion soup is one of the coziest recipes you can make in the wintertime. It's a classic recipe that has warmed hearts since the 18th century, offering a rich depth of flavor through slowly caramelized onions and a hearty, flavorful broth. Traditional French onion soup is made with beef stock, but a simple swap for vegetable broth makes this a vegetarian French onion soup recipe. Today, we're creating this recipe so it can be enjoyed by vegans, vegetarians, and people just looking to reduce their climate impact. 

This easy French onion soup recipe comes together in just under an hour with only 15 minutes of prep time and 30 minutes of cooking time. You don't need oven-proof bowls for this recipe, either; you can use what you have.  Here, I’ll walk you through a vegetarian French onion soup recipe that swaps traditional beef broth for a veggie-based mushroom broth, preserving all the umami flavor while keeping it plant-forward and cruelty-free. 

If you're here as a fellow soup lover looking for inspiration, make sure you check out our other soup recipes here!

Why This Vegetarian French Onion Soup Recipe?

This recipe keeps all the essentials of a good French onion soup: sweet onions caramelized to a golden brown, a splash of dry white wine for that extra depth, and a top layer of cheesy bread that gets melty and gooey in the oven. By adding mushrooms to the stock, we replicate the deep flavor you’d find in traditional recipes while making it a hearty, vegetarian-friendly option for everyone.

Ingredients and Equipment for the Perfect Bowl of Soup

• 2 large yellow onions, sliced thin
• 4 cloves garlic, minced
• 16 oz baby bella mushrooms, sliced
• 4 cups veggie broth (homemade vegetable stock if you have it)
• 1 splash of dry white wine 
• 1-2 tablespoons soy sauce for umami flavor
• Olive oil, for sautéing
• Salt and black pepper, to taste
• 1/4 tsp cumin
• Optional: splash of balsamic vinegar to enhance the depth of flavor
• Fresh thyme sprigs and bay leaves for seasoning

Topping Ingredients

• Baguette slices (or gluten-free bread if preferred)
• Cheese of choice: Gruyere, Mozzarella, Swiss, or vegan cheese for a vegan version

Equipment

• Large soup pot (or Dutch oven for best results)
• Baking sheet
• Wooden spoon
• Oven-proof bowls for individual servings (optional)

How to Make This Vegetarian French Onion Soup

Step 1: Caramelize the Onions

Start by heating your large soup pot over medium heat and adding a generous drizzle of olive oil. Add the sliced onions and cook, stirring often with a wooden spoon. Keep the heat at medium-low, allowing the onions to slowly caramelize, which may take up to 30 minutes. This slow cooking develops the beautiful golden brown color and sweet flavor essential to a good French onion soup. You can expedite the process by adding a bit of sugar and a pinch of salt to help the onions release their moisture. Check out our post here for some tips on how to caramelize onions.

Step 2: Add Garlic and Mushrooms

Once the onions are golden brown, add the minced garlic and sliced mushrooms. Stir and cook for about 5-7 minutes until the mushrooms release their moisture and start to brown, scraping the bottom of the pan with your wooden spoon to incorporate any browned bits. This is where all those complex, rich flavors come together!

Step 3: Deglaze and Build the Broth

Most of your mushrooms should be sticking to the bottom of the pan. Pour in a splash of white wine, allowing it to simmer, and cook down for about 2-3 minutes to burn off the alcohol and intensify the flavors.

Next, add the veggie broth, soy sauce, thyme sprigs, bay leaves, and a dash of black pepper. If you like a slightly more complex broth, consider a splash of balsamic vinegar and a pinch of cumin. Let everything come to a gentle simmer on medium-high heat, then reduce to medium-low and cook for about 20-30 minutes to let all the flavors meld.

Step 4: Toast the Bread & Cheese

Preheat your oven to 400°F. Arrange baguette slices in a single layer on a baking sheet. Then top them with some olive oil and preferred cheese. Toast them for about 5-7 minutes until they become crispy and golden. If you prefer a softer texture, you can skip this step and simply place fresh baguette slices on top of the soup later.

Step 5: Serve

Ladle soup into oven-proof bowls and place a slice of toasted bread with melty cheese on top of your bowl of soup. 

View this post on Instagram

---

Serving and Storing Tips

Serve the soup hot, garnished with a bit of fresh thyme if desired. This is the ultimate comfort food, perfect for warming up after a long day. If you have leftover soup, let it cool completely before transferring it to an airtight container and refrigerating. Reheat on the stove, adding a bit of extra veggie broth if it’s thickened too much.

Helpful Tips and Variations

• Make it Vegan: Substitute vegan cheese and use vegan butter for extra richness.
• Slow Cooker Option: You can adapt this recipe for a slow cooker by caramelizing the onions first, then adding all ingredients to the slow cooker and cooking on low for 6-8 hours.
• Gluten-Free Option: Use gluten-free bread for the topping.
• Blend the Soup: If you're looking for a different texture to your soup, 

This veggie-packed take on a classic French onion soup recipe is sure to become a staple in your collection of comforting soup recipes. Whether you’re embracing plant-based eating or simply looking for a vegetarian version of your favorite soup, this recipe hits all the marks. Curl up with a bowl on those chilly days and enjoy each spoonful of this flavorful broth, enhanced by caramelized onions, earthy mushrooms, and a melty cheese topping.

---