These Swiss Mushroom Burgers are big, juicy, and incredibly satisfying. At first glance, they almost look like classic beef burgers—but they’re actually completely vegetarian!
Large portobello mushrooms are roasted with garlic butter, topped with melted Swiss cheese, and served in soft burger buns loaded with fresh toppings. The result is a rich, savory burger packed with flavor and texture.
This recipe is faster and easier than most veggie burgers because there’s no need to form patties. The roasted mushroom becomes the star of the burger, delivering a juicy and “meaty” bite that even meat lovers enjoy.
❤️ Why You’ll Love These Mushroom Burgers
✔ Juicy and satisfying
✔ Simple ingredients
✔ No messy burger patties to shape
✔ Perfect vegetarian alternative
✔ Ready in under an hour
A great burger should always be:
- juicy
- hearty
- flavorful
- and filled with a proper burger portion in every bite
These mushroom burgers tick every box!
🍄 Ingredients
For the Mushrooms
- 4 large portobello or flat mushrooms
- 2 tbsp unsalted butter
- 2 garlic cloves, minced
- ½ tsp salt
- ½ tsp black pepper
- ½ tbsp olive oil
- 4 slices Swiss cheese
(or cheddar, Gruyère, Colby, or Jack)
For the Caramelized Onions
- 3 onions, sliced into rings
- 1 tbsp olive oil
- ¼ tsp salt
- ¼ tsp pepper
For the Pink Burger Sauce
- ⅔ cup mayonnaise
- 2 tbsp ketchup
- 1–3 tsp Sriracha (adjust to taste)
For the Burgers
- 4 burger buns (brioche works great)
- 8–12 lettuce leaves
- 2 tomatoes, sliced
Optional Sides
- French fries
- Baked potato wedges
👨🍳 How to Make Swiss Mushroom Burgers
1. Preheat the Oven
Preheat your oven to 450°F / 220°C (200°C fan).
2. Prepare the Garlic Butter
Melt the butter with minced garlic, salt, and pepper. Stir well.
3. Season the Mushrooms
Brush the smooth side of each mushroom with the garlic butter.
Place them gill-side up on a baking tray and brush the remaining butter inside the caps.
Drizzle lightly with olive oil.
4. Roast the Mushrooms
Roast the mushrooms for 25 minutes.
Flip them and roast for another 10 minutes until tender.
5. Add the Cheese
Place a slice of Swiss cheese on each mushroom and return them to the oven for 3 minutes until the cheese melts.
6. Cook the Onions
Heat olive oil in a skillet over medium-high heat.
Cook the onions for 5–7 minutes until golden and soft.
Season with salt and pepper.
7. Prepare the Sauce
Mix together:
- mayonnaise
- ketchup
- Sriracha
Set aside.
8. Assemble the Burgers
- Spread pink sauce on the bottom bun.
- Add lettuce and tomato slices.
- Place the cheesy roasted mushroom on top.
- Add caramelized onions.
- Spread a little sauce on the top bun and close the burger.
Serve immediately.
🍔 Optional Add-Ons
You can easily customize these burgers with extra toppings such as:
- avocado
- fried egg
- crispy bacon
- grilled pineapple
- roasted vegetables
- BBQ sauce or aioli
🍄 Can You Use Smaller Mushrooms?
Yes! If you can’t find large mushrooms, use smaller ones.
Simply:
- Slice them
- Sauté in garlic butter
- Pile them into a mound
- Add cheese and melt
- Use as the burger filling
The flavor will still be fantastic.
🍟 What to Serve with Mushroom Burgers
These burgers pair perfectly with:
- crispy French fries
- baked potato wedges
- coleslaw
- fresh green salad
😋 A Messy but Delicious Burger
Let’s be honest—there’s no elegant way to eat a juicy burger like this.
The mushrooms are incredibly juicy, the cheese is melty, and the sauce will definitely drip down your hands.
But that’s exactly what makes it so good.
Grab a stack of napkins and enjoy every bite!