Say hello to your new favorite weeknight meal! If you think a vegetarian burger can’t be hearty, juicy, and incredibly satisfying, this Portobello Mushroom Burger is here to change your mind. We’re using the ‘steak’ of the veggie world, a large and meaty portobello mushroom, and pan-searing it to perfection with sweet onions and gooey melted Swiss cheese. Served open-faced on a toasty English muffin, this burger is simple, affordable, and bursting with gourmet flavor. Let’s get cooking!
Ingredients
• 1 English muffin, split
• 2 teaspoons / 10g (0.35 oz) butter, divided
• 1 large portobello mushroom
• 1 romaine lettuce leaf
• 1 teaspoon / 5ml (0.2 fl oz) olive oil
• 3 tablespoons / 28g (0.99 oz) chopped onion
• 1 thick tomato slice
• 2 tablespoons / 14g (0.49 oz) grated Swiss cheese
Instructions
1. Toast the English muffin halves until golden. While still warm, spread 1 teaspoon (5 ml / 0.2 fl oz) of butter on the cut side of each half and set aside.
2. Prepare your vegetables. Gently wipe the portobello mushroom clean with a damp cloth and cut it into thin, even slices. Wash and pat dry the romaine lettuce leaf.
3. In a skillet over medium heat, warm the olive oil. Add the chopped onion and cook, stirring occasionally, until tender and fragrant.
4. Add the remaining 1 teaspoon (5 ml / 0.2 fl oz) of butter to the skillet. Push the cooked onions to one side and arrange the portobello mushroom slices in a single layer. Cook for about 2 minutes until the bottom is browned.
5. Flip the mushroom slices and cook the other side until browned. While the second side is cooking, add the tomato slice to a space in the pan to warm it through.
6. Once the mushroom slices are browned on both sides, sprinkle the grated Swiss cheese evenly over the top. Continue to cook for another minute, or until the cheese is perfectly melted and bubbly.
7. Assemble your burger. Place the warmed tomato slice on one muffin half and the sautéed onions on the other. Carefully lay the cheesy mushroom slices over the top and garnish with the fresh lettuce. Serve immediately, open-faced.
Nutritional Information
• Approximate values per serving
• Calories: 332
• Fat: 17g
• Carbohydrates: 34g
• Protein: 10g
• Fiber: 4g
• Sugar: 4g
• Sodium: 303mg
Pro Tips
• for the Perfect Burger
• For an extra flavor boost, marinate the portobello mushroom for 15-20 minutes in a mix of balsamic vinegar, soy sauce, and garlic powder before cooking.
• Don’t have Swiss cheese? Provolone, Gruyère, or even a sharp cheddar melt beautifully and pair wonderfully with the earthy mushroom.
• Elevate your burger by spreading a thin layer of pesto or garlic aioli on the toasted English muffin before adding the other toppings.
FAQ
Q: Can I make this portobello mushroom burger vegan
A: Absolutely! To make this burger vegan, simply use a plant-based butter and a dairy-free Swiss-style cheese. Also, ensure your English muffin is vegan, as some brands contain dairy or honey.
Q: How can I add more protein to this vegetarian burger
A: For a simple protein boost, you can spread a layer of hummus on the toasted English muffin or serve the burger alongside a quinoa salad or roasted chickpeas. Adding a plant-based patty under the mushrooms is also a great option.
Q: What’s the best way to store and reheat leftovers
A: For best results, store the cooked mushroom and onion mixture in an airtight container in the refrigerator for up to 2 days. Reheat the mixture in a skillet over medium heat until warmed through, then assemble on a freshly toasted English muffin just before serving.
Q: Can I grill the portobello mushroom instead of pan-searing it
A: Yes, grilling is a fantastic alternative. For a whole mushroom cap, marinate it first (as suggested in the pro tips), then grill over medium-high heat for 4-6 minutes per side until tender and showing grill marks. Top with cheese during the last minute of cooking to melt.
More Recipes You’ll Love
- Orange and Ginger Mixed-Veggie Stir-Fry
- Vegetarian Asian Lettuce Wrap Sandwich
- Simple Sautéed Portobello Mushrooms
Hearty Portobello Mushroom Burger
Ingredients
Method
- Toast the English muffin halves until golden.
- While still warm, spread 1 teaspoon (5 ml / 0.2 fl oz) of butter on the cut side of each half and set aside.
- Prepare your vegetables. Gently wipe the portobello mushroom clean with a damp cloth and cut it into thin, even slices. Wash and pat dry the romaine lettuce leaf.
- In a skillet over medium heat, warm the olive oil.
- Add the chopped onion and cook, stirring occasionally, until tender and fragrant.
- Add the remaining 1 teaspoon (5 ml / 0.2 fl oz) of butter to the skillet. Push the cooked onions to one side and arrange the portobello mushroom slices in a single layer.
- Cook for about 2 minutes until the bottom is browned.
- Flip the mushroom slices and cook the other side until browned.
- While the second side is cooking, add the tomato slice to a space in the pan to warm it through.
- Once the mushroom slices are browned on both sides, sprinkle the grated Swiss cheese evenly over the top.
- Continue to cook for another minute, or until the cheese is perfectly melted and bubbly.
- Assemble your burger.
- Place the warmed tomato slice on one muffin half and the sautéed onions on the other. Carefully lay the cheesy mushroom slices over the top and garnish with the fresh lettuce.
- Serve immediately, open-faced.
- Don't have Swiss cheese? Provolone, Gruyère, or even a sharp cheddar melt beautifully and pair wonderfully with the earthy mushroom.
