This vegan onion soup is a warm hug in a bowl.
It’s rich, savory, and super comforting. We’re talking deep golden caramelized onions, simmered in a flavorful broth, and topped with crusty bread and melty dairy-free cheese.
It tastes fancy but it’s honestly really simple to make.
I’ve been making this for years and it never disappoints, especially on cold nights or when I just want something soothing.
What You’ll Need
- 4 large yellow onions, thinly sliced
- 2 tablespoons olive oil
- 1 tablespoon vegan butter
- 1 teaspoon salt
- 1 teaspoon sugar
- 2 cloves garlic, minced
- ½ cup dry white wine (or more broth if avoiding alcohol)
- 6 cups low-sodium vegetable broth
- 1 tablespoon soy sauce or tamari
- 1 teaspoon dried thyme
- 1 bay leaf
- Fresh cracked black pepper to taste
- 4 slices of crusty bread (like baguette), toasted
- 1 cup shredded vegan mozzarella cheese
- Chopped parsley (optional, for garnish)
Ingredients
Pro Tips
- Slice your onions evenly so they caramelize at the same rate
- Don’t rush the onions — low and slow makes them sweet and rich
- Toast the bread well so it doesn’t get soggy too fast
- Use a wine you’d actually drink — it adds a lot of flavor
- Vegan cheese melts better when broiled, not just added cold
Tools You’ll Need
- Large heavy-bottomed pot
- Sharp chef’s knife
- Cutting board
- Wooden spoon
- Soup bowls
- Oven-safe ramekins or bowls (for melting cheese)
- Baking sheet (for toasting bread)
Substitutions and Variations
- Use shallots instead of yellow onions for a twist
- Swap white wine with a splash of apple cider vinegar for tang
- Use gluten-free bread for a GF version
- Try vegan Gruyère or smoked provolone cheese for variety
- Add a splash of balsamic vinegar for deeper flavor
Make Ahead Tips
- You can caramelize the onions up to 3 days ahead and keep them in the fridge
- The soup itself stores well in the fridge for 4–5 days — just reheat and top with fresh toast and cheese
- Freeze the soup (without bread or cheese) for up to 3 months
Step-by-Step Instructions
Step 1: Caramelize the Onions
Add 2 tablespoons olive oil and 1 tablespoon vegan butter to a large pot over medium heat. Once melted, add 4 large yellow onions, thinly sliced, along with 1 teaspoon salt and 1 teaspoon sugar. Stir well and cook, stirring occasionally, for about 35–40 minutes until onions are deeply golden and caramelized.
Step 2: Add Garlic and Wine
Add 2 cloves of minced garlic to the caramelized onions. Stir and cook for 1 minute. Then pour in ½ cup dry white wine. Scrape the bottom of the pot to release any brown bits. Let it simmer for 2–3 minutes to cook off the alcohol.
Step 3: Add Broth and Seasonings
Add 6 cups vegetable broth, 1 tablespoon soy sauce, 1 teaspoon dried thyme, 1 bay leaf, and a few cracks of black pepper. Stir to combine. Bring to a simmer and let cook for 20 minutes, uncovered.
Step 4: Toast the Bread
While the soup simmers, place 4 slices of crusty bread on a baking sheet and toast in the oven at 375°F for about 8–10 minutes, until golden and crisp.
Step 5: Assemble and Broil
Ladle hot soup into oven-safe bowls. Place one toasted bread slice on top of each bowl, sprinkle with ¼ cup shredded vegan mozzarella cheese. Broil for 2–4 minutes until cheese is melted and bubbly. Garnish with parsley if you like.
Leftovers and Storage
- Store leftover soup (without bread or cheese) in the fridge for up to 5 days
- Reheat on the stove or in the microwave
- Toast fresh bread and add cheese just before serving for the best texture
- Freeze the soup base in airtight containers for up to 3 months
Why I Love This Recipe
This soup takes me back to the first cozy fall I spent trying to recreate my favorite bistro soup — but without the beef broth or dairy. I wanted something rich, deeply flavored, and just as comforting. And this nailed it.
- It’s totally plant-based but doesn’t taste like it
- That deep onion flavor is next level
- The broiled cheesy bread? Absolute perfection
- Feels fancy but it’s so easy
- A great one-pot recipe for lazy days or dinner parties
Servings & Time
Serves: 4
Total time: 1 hour
Macros (per serving)
- Calories: 320
- Protein: 7g
- Fat: 13g
- Carbs: 42g
- Fiber: 4g
- Sugar: 9g
Why This Recipe Works (Quick Science)
Caramelizing onions breaks down their natural sugars, giving that deep, sweet flavor. Deglazing with wine lifts all the browned bits (a.k.a. flavor bombs) from the pot. Simmering the broth with thyme and soy sauce gives it that rich umami usually found in beef-based versions — without any meat.
Common Mistakes
- Rushing the onions – If they’re pale, they’re not ready. Give them time to caramelize
- Skipping the deglaze – That step adds so much depth of flavor
- Using sweet wine – Dry wine gives the best savory balance
- Adding cheese too early – Only broil it at the end or it’ll melt into the soup
What to Serve With
- Simple green salad with lemon vinaigrette
- Roasted Brussels sprouts
- A glass of dry white wine or sparkling water with lemon
- Extra toasted baguette slices for dipping
- Herby white bean salad
FAQ
Can I make this gluten-free?
Yes, just use gluten-free bread and make sure your soy sauce is GF (or use tamari).
Is this freezer-friendly?
The soup base is! Just freeze without the bread and cheese.
Can I skip the wine?
Yes, just use extra broth and add a splash of vinegar or lemon juice for acidity.
What vegan cheese melts best?
Look for one labeled “melts well” — vegan mozzarella shreds usually do best.
Can I use red onions?
You can, but they’ll make the soup a bit sweeter and darker. Yellow onions work best here.
Now it’s your turn — make this bowl of warm, rich vegan onion soup and let me know how it goes! I’d love to hear how yours turns out, and feel free to drop a comment if you have questions or tweaks.