Name: The Best Grilled Portobello Mushroom Burger Recipe
Prep time: 10 min
Cook time: 15 min
Total time: 1 h
Cuisine: American
Ingredients: 4 portobello mushroom caps; 2 tbsp balsamic vinegar; 1 tbsp low sodium soy sauce; 1 tbsp olive oil; 1 tbsp chopped rosemary; 1½ tsp steak seasoning like Montreal Steak Grill Mates; 4 thick slices red onion; 4 oz reduced fat Swiss cheese, sliced thin; 4 thin slices tomato; ½ avocado, sliced thin; Baby spinach; 4 whole wheat low calorie buns (e.g., Martin brand)

Jump to Recipe· 4.2 from 13 reviews

“`html

If you’re craving a juicy, flavorful burger that’s packed with hearty textures and vibrant freshness, you’ve got to try The Best Grilled Portobello Mushroom Burger Recipe. This recipe transforms simple portobello caps into a savory masterpiece with a tangy marinade, melted Swiss cheese, and crisp veggies layered perfectly on a toasted whole wheat bun. It’s a satisfying alternative to beef burgers that will thrill vegetarians and meat-eaters alike, making it a guaranteed crowd-pleaser at any backyard cookout or cozy dinner. Get ready to indulge in a rich umami experience with every bite!

Ingredients You’ll Need

This image shows two Portobello mushroom burgers on a white marbled surface. Each burger has a bottom bun topped with fresh green spinach leaves, a cooked large Portobello mushroom cap covered with melted white cheese, and a round slice of raw red onion on top. The top bun is open and placed behind the bottom part, with red tomato slices and green avocado slices layered neatly. The buns are light brown, soft, and slightly toasted. Photo taken with an iphone --ar 4:5 --v 7

These ingredients are straightforward yet essential, each bringing unique flavor, texture, or color that elevates the dish. Together, they create a balanced and irresistible burger that’s both hearty and fresh.

4 portobello mushroom caps: The meaty base that soaks up all the marinade flavors beautifully.
2 tbsp balsamic vinegar: Adds a subtle tang and deep sweetness to the marinade.
1 tbsp low sodium soy sauce: Brings a rich, savory umami depth without overpowering the mushrooms.
1 tablespoon olive oil: Helps the marinade coat evenly and assists with grilling.
1 tbsp chopped rosemary: Fresh herbaceous notes that complement the earthy mushrooms.
1½ tsp steak seasoning like Montreal Steak Grill Mates: Infuses a bold, smoky spice profile.
4 thick slices red onion: Grilled for caramelized sweetness and crunch.
4 oz reduced fat Swiss (sliced thin): Melts perfectly over the mushrooms for creamy, mild cheese goodness.
4 thin slices tomato: Adds juicy brightness and a fresh contrast.
½ avocado (sliced thin): Creamy texture that rounds out the burger with richness and healthy fats.
Baby spinach: A peppery green layer that’s nutritious and crisp.
4 whole wheat low-calorie buns: Toasted to provide a wholesome, slightly nutty foundation.

How to Make The Best Grilled Portobello Mushroom Burger Recipe

Step 1: Prepare the Marinade and Mushrooms

Start by whisking together the balsamic vinegar, soy sauce, olive oil, chopped rosemary, and Montreal steak seasoning in a large bowl. This marinade is the magic behind the bold flavors that soak into the mushroom caps. Place the mushrooms in the marinade and turn them a few times to ensure even coating. Let them rest at room temperature for 20 to 30 minutes to fully absorb those delicious flavors.

Step 2: Heat the Grill and Prepare for Cooking

While the mushrooms are marinating, preheat your grill or indoor grill pan over medium heat. Lightly oil the grill grates or spray the pan with a bit of cooking spray to prevent sticking. This step ensures a perfect sear and those gorgeous grill marks that add so much character to the portobello burgers.

Step 3: Grill the Mushrooms and Onions

Place the marinated mushrooms on the grill, reserving the marinade for basting. Grill each side for about 5 to 7 minutes, basting frequently to keep the caps moist and flavorful. When you have about one minute left, add the thin Swiss cheese slices on top so they melt beautifully. At the same time, grill the red onion slices for roughly a minute on each side until tender and slightly caramelized. Don’t forget to toast the buns on the grill until they are warm and lightly crisp.

Step 4: Assemble Your Burger

Now comes the fun part—constructing your burger! Place a handful of fresh baby spinach on the bottom bun, then layer on the cheesy grilled portobello mushroom. Next, add the sweet grilled onions, slices of tomato, and avocado. Close it up with the top bun and get ready for an explosion of flavors and textures in every bite.

How to Serve The Best Grilled Portobello Mushroom Burger Recipe

A close-up of a sandwich with a soft brown bun on top and bottom. Inside, there are several layers: at the bottom is a dark, thick grilled patty with melted white cheese over it. Above the cheese, there is a thick slice of red onion, several slices of green avocado, green leafy lettuce, and two slices of bright red tomato. In the background, there is a similar sandwich slightly blurred on a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

To make your burger shine even more, consider adding some crunchy pickles, a dollop of garlic aioli, or a sprinkle of freshly cracked black pepper. These small touches add layers of flavor and make your grilled mushroom burger uniquely yours.

Side Dishes

This burger pairs wonderfully with crispy sweet potato fries, a fresh garden salad, or even a simple side of grilled corn on the cob. These accompaniments bring complementary flavors and keep the meal balanced and exciting.

Creative Ways to Present

For an eye-catching presentation, stack your burger with colorful layers visible from the sides and serve it on a rustic wooden board. Add a toothpick through the center to keep everything intact, and sprinkle a little fresh rosemary or parsley around the plate to enhance the aroma and appeal.

Make Ahead and Storage

Storing Leftovers

If you have any leftover grilled portobello burgers, wrap them tightly in plastic wrap or place them in an airtight container and refrigerate for up to 2 days. The flavors hold up well, especially if you keep the avocado separate to prevent browning.

Freezing

While fresh is always best with this recipe, you can freeze the grilled mushrooms alone (without fresh veggies or buns) by placing them in a freezer-safe bag for up to 3 months. Thaw them overnight in the fridge before reheating gently to maintain texture.

Reheating

Reheat your grilled portobello mushrooms in a preheated oven at 350°F for about 10 minutes or on a stovetop grill pan to bring back that delicious smoky flavor. Add fresh spinach, tomato, and avocado when assembling to keep the burger fresh and vibrant.

FAQs

Can I use other types of mushrooms for this burger?

Portobello mushrooms have the perfect size and meaty texture for grilling and holding all the toppings. While other mushrooms can be used, they may not provide the same structure and robust flavor.

Is this recipe suitable for vegans?

This recipe as written includes Swiss cheese, which is not vegan, but you can easily swap it with your favorite vegan cheese or omit it altogether for a delicious vegan version.

Can I prepare the marinade in advance?

Absolutely! Making the marinade a day ahead lets the flavors meld even more. Just keep the mushrooms separate until you’re ready to marinate and grill.

What can I substitute for the whole wheat buns?

Feel free to use gluten-free buns, brioche, or even large lettuce leaves for a low-carb alternative. The burger tastes fantastic no matter the bun choice.

How do I ensure the mushrooms don’t get soggy on the grill?

Marinating just long enough and grilling over medium heat while basting will keep the mushrooms juicy but not soggy. Avoid over-marinating and preheat your grill properly for the best sear.

Final Thoughts

Trying out The Best Grilled Portobello Mushroom Burger Recipe is like unlocking a new realm of burger enjoyment that’s full of vibrant flavors and satisfying textures. Whether you’re a vegetarian or simply looking for something fresh and hearty, this recipe will become one of your go-to favorites. So fire up the grill, gather your ingredients, and dive into a delicious, wholesome burger experience you’ll want to share again and again!

“`

The Best Grilled Portobello Mushroom Burger Recipe

Ingredients You’ll Need

How to Make The Best Grilled Portobello Mushroom Burger Recipe

Step 1: Prepare the Marinade and Mushrooms