Easy Mushroom Burgers (Ready in 20 Minutes)

Name: Easy Mushroom Burgers (Ready in 20 Minutes)
Prep time: 5 min
Cook time: 15 min
Total time: 20 min
Ingredients: 4 portobello mushrooms (stem and gills removed); 1 large sweet onion (thinly sliced); 4 tablespoons unsalted butter (divided); 3 tablespoons olive oil (divided); 1 ½ teaspoon kosher salt (divided); 1 teaspoon garlic powder; 1 cup gouda cheese (shredded or your favorite cheese); 2 cups arugula (divided); ¼ cup Truff spicy mayonnaise (or plain mayonnaise); 4 burger buns

If you’re craving a meat-free burger, these Mushroom Burgers are the ultimate savory, juicy alternative to classic beef! Portobello mushrooms bring a rich, umami depth and a satisfyingly meaty texture. Paired with sweet caramelized onions, melted gouda, and spicy mayo, every bite is guaranteed to impress.

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Mushroom burgers with toppings and fries.

Why This Recipe Works

I love big, bold flavors, but sometimes I want a lighter alternative to beef burgers. Enter this mushroom burger recipe! Portobello mushrooms are my favorite vegetarian patty—they’re smoky, umami-packed, and deliver a juicy texture that feels just as indulgent as a classic burger.

I like to keep things nice and simple for this recipe, too. Everything comes together in one pan and under 20 minutes, making it perfect for busy weeknights or impromptu backyard get-togethers with friends.

With buttery, pan-seared mushrooms, melty gouda, and sweet caramelized onions, each bite is packed with savory deliciousness. Whether you’re vegetarian or just looking to switch up your burger routine, this recipe is an easy hit!

Ingredients

Portobello Mushrooms: These large, meaty mushrooms make the perfect burger patty. Look for firm mushrooms without bruising or excess moisture, and remove the stems and gills to ensure a smooth texture.
Sweet Onion: I like to use sweet onion for caramelizing to add a rich, sweet, and savory depth to the burger. Cook them low and slow in butter to bring out their natural sugars.
Unsalted Butter: Used to caramelize the onions and cook the mushrooms. Unsalted butter allows for better control over the saltiness of the burgers.
Olive Oil: Helps prevent the butter from burning. Use extra-virgin olive oil here!
Kosher Salt: Enhances all the flavors and draws out moisture from the mushrooms.
Garlic Powder: Adds a subtle, mellow garlic flavor without overpowering the recipe.
Gouda Cheese: Melts beautifully over the mushrooms, adding a creamy, smoky flavor.
Arugula: Offers a fresh, peppery contrast to the richness of the mushrooms and cheese.
Truff Spicy Mayonnaise: Adds a bold, creamy kick. If you can’t find Truff mayo, you can just mix regular mayonnaise with a little Sriracha or your favorite hot sauce.
Burger Buns: Brioche, pretzel buns, or whole grain buns all work well! Make sure to toast them for a crispy texture and to prevent the mushrooms from making them soggy.

Cleaning and cooking portobello mushrooms.

Instructions

Caramelize the Onions: Peel and slice the onion thinly. Heat a pan over medium heat, add a tablespoon of butter and 2 tablespoons olive oil, then add the onions and salt. Cook for 15 minutes, stirring frequently, until golden and soft.
Prep the Mushrooms: Remove the stems and gently scoop out the gills using a spoon. Brush both sides with olive oil, then season with salt and garlic powder.
Cook the Mushrooms: Heat another pan over medium-low heat and melt 3 tablespoons of butter. Place the mushrooms in the pan, top-side up, pressing them down slightly. Cover and cook for 5 minutes.
Melt the Cheese: Flip the mushrooms, then divide the shredded gouda evenly between them. Cover with a lid, reduce heat to low, and cook until the cheese is melted.
Assemble the Burgers: Toast the buns, then spread spicy mayo on both sides. Layer with arugula, the cheesy mushroom patties, and caramelized onions. Top with the bun and enjoy!

Substitutions & Variations

Cheese Options: Feel free to swap gouda for cheddar, Swiss, brie, or provolone to create different flavor profiles.
Mayo Alternatives: You can use garlic aioli, pesto mayo, or chipotle sauce instead of spicy mayo—whichever sauce you prefer!
Bun Choices: Try ciabatta buns, sourdough rolls, pita breads, or kaiser rolls.
Extra Toppings: Add avocado, raw or pickled onions, sliced tomatoes, mustard, roasted red peppers, butter lettuce, or even a fried egg for extra layers of flavor.
Gluten-Free: Use gluten-free burger buns or serve your mushroom burgers between lettuce wraps to keep things low-carb!
Vegan-Friendly: For a fully plant-based mushroom burger, use any vegan butter, dairy-free cheese, and egg-free mayo mixed with Sriracha.

Storing & Reheating

If you have leftovers, here’s how to keep your mushroom burgers fresh:

Fridge: Store the cooked burgers in an airtight container for up to 3 days. Keep the mushroom patties and toppings separate from the buns for the best texture.
Reheating: Warm the mushrooms in a skillet over medium heat for a few minutes or in the microwave for 30-45 seconds. Toast the buns, then assemble with toppings!
Prep Ahead: Caramelize the onions up to 3 days in advance and store them in the fridge. The mushrooms can be cleaned and stored a day ahead for quicker cooking.

Expert Tips

Press the Mushrooms: Gently pressing the mushrooms into the pan helps release excess moisture and gives them a meatier texture.
Use a Lid for the Cheese: This traps the steam, ensuring even cheese melting without drying out the mushroom patties.
Add Extra Seasoning: If you love bold flavors, try brushing on a drizzle of balsamic glaze or a dash of smoked paprika to the mushrooms before cooking.
Patience is Key: Low and slow cooking brings out the natural sweetness in the onions. It may be tempting, but don’t turn the heat up or you run the risk of burning them.

FAQs

How do I prevent the mushrooms from becoming soggy?

Pat the mushrooms dry before cooking and avoid overcrowding the pan. Also, don’t flip them too soon—let them sear properly before flipping to the second side.

Can I grill the mushrooms instead of pan-searing them?

Absolutely! Brush them with olive oil and grill over medium heat for about 5 minutes per side. Add the cheese slices after the first flip.

Do I have to remove the mushroom gills?

Removing the gills helps prevent the burger from becoming too moist and makes the texture better. However, it’s optional if you prefer to keep them on.

If you enjoyed these mushroom burgers, check out some more fan-favorite burgers like these:

If you try this Mushroom Burger recipe, let me know what you think! Rate and review this recipe in the comments below. Don’t forget to take a picture and tag me on Instagram @lenaskitchenblog!