These portobello mushroom burgers are one of the most satisfying vegetarian sandwiches you can make at home. They look and feel like classic burgers, but rely on meaty, marinated portobello caps for flavor and texture—perfect for backyard grilling, weeknight dinners, or when you want a simple meatless meal that doesn’t skimp on taste.
The BEST Portobello Mushroom Burger Recipe
Even people who usually prefer meat will enjoy these mushroom burgers. The key is a robust marinade that soaks into the mushroom caps and delivers a savory, slightly sweet, umami-rich flavor. Once grilled and topped with your favorite condiments and cheese, these portobellos make a juicy, satisfying sandwich.
We keep the toppings simple in this version: grilled red onion, pepper jack cheese for a little heat, fresh greens, and a quick hummus-ketchup sauce that adds creaminess and tang. Feel free to swap in your favorite buns, cheeses, or additional toppings—these burgers are very adaptable.
Why you’ll love it!
Juicy, full-flavored mushroom burgers that satisfy like a traditional burger.
A quick and easy vegetarian main that’s great for grilling season.
Ideal for introducing non-vegetarians to meatless meals.
The marinade is simple but transforms the mushrooms completely.
Featured Ingredients
- Portobello mushrooms: Choose large, firm caps—these are about the right size to replace burger patties and bring an earthy, meaty texture.
- Red onion: Sliced into rounds and grilled until tender and slightly charred for sweetness and depth.
- Pepper jack cheese: A melty, slightly spicy option—swap for your preferred cheese or a plant-based alternative.
- Chopped greens: Arugula, spinach, romaine, or mixed greens add freshness and crunch.
- Sweet onion burger buns: Any sturdy hamburger bun works; onion buns add extra flavor.
- Garlic hummus: Used in the quick sauce for creaminess and savory garlic flavor.
- Ketchup: Adds familiar sweetness and tang to balance the hummus.
Try it
Grilled Portobello Mushrooms
These grilled portobellos also work great as a side or a simple main—season, grill, and serve with a salad for a lighter meal.
What’s in the homemade marinade?
The marinade is the heart of this recipe. It balances salty, sweet, tangy, and savory notes so the mushrooms take on a rich, beefy flavor. Ingredients:
- Worcestershire sauce
- Balsamic vinegar
- Fresh lemon juice
- Olive oil
- Garlic (minced)
- Grated onion
- Light brown sugar
- Dijon mustard
Simple Instructions
Prepare the Marinade
Add all the marinade ingredients to a large bowl and whisk until smooth and combined.
Marinate the Mushrooms
Brush or dredge the mushroom caps in the marinade a few times so they’re well coated. Let them sit in the marinade for 1 hour, flipping them halfway through to ensure even flavor.
Preheat the Grill
Preheat your grill to 400ºF and clean the grates so the mushrooms don’t stick.
Season and Grill Onions
Place the onion rounds on a plate, drizzle with olive oil, and season with salt and pepper. Grill the onions over indirect heat for about 10 minutes, flipping once, until soft and slightly charred.
Grill the Mushrooms
Place mushrooms cap side down over indirect heat. Grill 3 minutes on the cap side, flip, and grill an additional 2 minutes. Add a slice of cheese to each cap, close the grill for 1 minute to melt the cheese, then remove.
Make the Sauce
While the mushrooms cook, whisk together ½ cup garlic hummus and ½ cup ketchup until smooth. This creamy, tangy sauce complements the char and umami of the mushrooms.
Assemble the Burger
To assemble, place the bottom bun on a plate and add about ½ cup chopped greens. Top with the grilled mushroom cap, a few grilled onion rounds, and any additional toppings you like. Spread 2–3 tablespoons of the hummus-ketchup sauce on the top bun, close the burger, and serve immediately.
Topping Ideas
Customize your portobello burger with any of these additions:
- Avocado slices
- Fried egg
- Roasted or grilled peppers
- Caramelized onions
- Pesto
- BBQ sauce
- Pickles
- Sliced jalapeños
- Dijon mustard
Storage
Store leftover grilled mushrooms in an airtight container in the refrigerator for up to 3 days. Keep the mushrooms separate from the buns and fresh toppings to prevent sogginess—pack greens and buns in small containers or bags and add them when you’re ready to eat.
Can I freeze portobello mushroom burgers?
Freezing is not recommended. Mushrooms lose texture when frozen and reheated, so these burgers are best enjoyed fresh or within a few days refrigerated.
Photography: Photos in this post were taken by Ashley McGlaughlin from The Edible Perspective.
Recipe Details
Servings: 4 • Prep: 1 hour 20 minutes • Cook: 17 minutes • Total: 1 hour 37 minutes
Ingredients
Marinade
- 1 tablespoon Worcestershire sauce
- 2 tablespoons balsamic vinegar
- 2 tablespoons fresh lemon juice
- 3 tablespoons olive oil
- 3 garlic cloves, peeled and minced
- 1 tablespoon grated onion
- 1 teaspoon light brown sugar
- 1 teaspoon Dijon mustard
Other Ingredients
- 4 large portobello mushrooms, destemmed, rinsed, and dried
- ½ teaspoon kosher salt (for the mushrooms)
Burger Ingredients
- 1 large red onion, sliced into rounds
- 1 tablespoon olive oil (for the onions)
- 1 teaspoon kosher salt (for the onions)
- 4 slices pepper jack cheese
- 2 cups chopped greens (arugula, spinach, romaine, etc.)
- 4 sweet onion burger buns
Sauce
- ½ cup garlic hummus
- ½ cup ketchup
Tips & Notes
- Choose large, firm portobello caps for best texture and grillability.
- Adjust the marinade balance to your taste—more balsamic for acidity, more brown sugar for sweetness, or extra Dijon for bite.
- Use plant-based cheese and hummus to make this recipe fully vegan.
Nutrition (per serving, approximate)
Calories: 382 kcal, Carbohydrates: 45 g, Protein: 10 g, Fat: 19 g, Fiber: 5 g, Sugar: 16 g