Grilled Portobello Mushroom Burger

4.80 from 20 votes
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This grilled portobello mushroom burger recipe makes for a tasty vegetarian meal. The mushroom caps are marinated in a tangy balsamic vinegar for maximum flavor.

Easy and delicious portobello mushroom burger recipe.

Recipe Science

  • Grilling portobello mushrooms releases their moisture and intensifies their umami flavor as the natural sugars caramelize through the Maillard reaction.
  • The high water content of portobello mushrooms keeps them juicy during grilling, while their dense texture mimics the heartiness of a meat-based burger.
  • Marinating the mushrooms before grilling allows the flavors to penetrate, enhancing the overall taste and ensuring a well-seasoned, flavorful burger.

Why It Works

These portobello mushroom burgers will impress even the most devoted meat lover. When cooked, mushrooms have incredible umami and natural meaty flavors. The size and thickness of the caps make them perfect for grilling, and they fit nicely inside toasted burger buns.

There are a few key preparation steps. The gills or brown stuff underneath the cap must be scraped out. The cleaned caps are then briefly marinated in a balsamic vinegar and soy sauce mixture. Grilling both sides of the caps tenderizes the mushrooms while adding a smoky, charred texture to the surface.

Ingredients You’ll Need

  • Portobello mushrooms: Serve as the “burger patty,” offering a meaty texture and rich umami flavor.
  • Extra-virgin olive oil: Adds moisture and helps the mushrooms cook evenly on the grill.
  • Balsamic vinegar: Provides a tangy sweetness that enhances the flavor of the mushrooms.
  • Soy sauce: Adds a savory, umami-rich depth to the marinade, complementing the natural flavor of the mushrooms.
  • Minced garlic: Infuses the mushrooms with a robust, aromatic flavor.
  • Kosher salt and black pepper: Season the mushrooms to bring out and balance all the other flavors.
  • Burger buns: Provide the soft, sturdy base to hold the grilled mushrooms and toppings.

See the recipe card below for all ingredients and measurements (US and metric).

Ingredient Substitutions

  • Portobello mushrooms: Substitute with large, thick slices of eggplant for a different vegetable-based burger option.
  • Extra-virgin olive oil: Use avocado oil or melted coconut oil for a different fat with a mild flavor.
  • Balsamic vinegar: Replace with red wine vinegar or apple cider vinegar for a different tangy flavor.
  • Soy sauce: Use tamari for a gluten-free alternative, or coconut aminos for a soy-free option.
  • Burger buns: Swap with lettuce wraps or whole wheat buns for a lower-carb or more nutritious choice.

How to Make Portobello Mushroom Burgers

Person removing the stem and gills from a portobello mushroom with a spoon.

Step 1: Prepare the Mushrooms

The key to delicious mushroom patties is properly cleaning and preparing the caps. First, remove the stems and brown gills under the cap. Trim off the stem and scoop out the gills with a large spoon.

The brown sections will easily lift off. This is especially important because it can give the mushrooms a muddy flavor. Clean the tops with a damp cloth to remove any dirt.

Knife scoring the top of a mushroom cap.

Step 2: Score the Tops

When cooked, the outer surface of the large mushroom cap can become chewy. To tenderize and make it easier to chew, create a shallow cross-hatched pattern on top to help break up the skin. A bonus is that more of the marinade gets infused into the mushroom beneath that thicker top layer.

Step 3: Make the Marinade

Whisk together olive oil, vinegar, soy sauce, minced garlic, salt, and pepper in a small bowl.

Portobello mushrooms marinating in vinegar mixture.

Step 4: Marinate the Mushrooms

Mushrooms already have a strong natural umami flavor, which comes from glutamic acid and nucleotides that enhance the taste. However, a brief 30-minute soak bumps up the taste factor to absolutely delicious.

To make an imitation beef burger, the fungi are coated with a mixture of balsamic vinegar, soy sauce, olive oil, garlic, salt, and pepper. The process works just like marinating meat and poultry before grilling.

Step 5: Prepare the Grill

Preheat the grill over medium-high heat, 350 to 400ºF (177 to 204ºC). Clean and grease the cooking grates with metal tongs and a paper towel dipped in oil.

Portobello mushroom caps grilling on a barbecue.

Step 6: Grill the Mushrooms

Remove the mushrooms from the marinade and place them on the hot grill, cap-side down. Cover and cook until the mushrooms have released their liquid with charred marks, 4 to 6 minutes.

Portobello mushroom caps with grill marks.

Flip and cook covered for 3 to 5 minutes. If adding cheese, place it on after flipping, then cover and cook until melted.

The goal is to get a lightly charred portobello mushroom that’s also tender and juicy. While the moisture is released, the marinade continues to infuse into the mushroom. Grilling allows most moisture to evaporate so the burger is not soggy when added to the toasted bread.

Various topping ingredients to make mushrooms burgers.

Step 7: Ready to Serve

Add your favorite toppings, such as homemade mayonnaise, sliced avocado, ripe tomatoes like beefsteak, and crisp and tender lettuce like butter leaf. Various cheeses, such as sharp cheddar, Swiss cheese, or fresh mozzarella, can also elevate the flavor.

Frequently Asked Questions

Can mushrooms be washed?

You can gently rinse mushroom caps, as they are covered with a water-repelling protein called hydrophobins. The issue is that when the gills underneath are exposed to water, they act like sponges, soaking up moisture and creating a soggy product. That’s why mushrooms, especially portobellos, should never be soaked in water.

Which side of a portobello should you grill first?

When grilling portobello mushrooms, start by grilling them gill-side up first. This allows the mushroom to release moisture without losing its juices. After a few minutes, flip it over to grill the gill-side down, allowing it to absorb the marinade and achieve a nice char on both sides.

Serve This With

If you tried this Grilled Portobello Mushroom Burger recipe, please leave a 🌟 star rating and let me know how it went in the 📝 comments below!

Portobello Mushroom Burger

Portobello mushroom burgers marinated in a tangy balsamic vinegar mixture and grilled on the barbecue for maximum flavor. A tasty vegetarian meal.
4.80 from 20 votes
Prep Time1 hour
Cook Time15 minutes
Total Time1 hour 15 minutes
Servings 4 servings
Course Entree
Cuisine American

Ingredients 
 

  • 4 portobello mushrooms, 4 to 5" in diameter, with stems and gills removed
  • cup extra-virgin olive oil
  • 3 tablespoon balsamic vinegar
  • 1 tablespoon soy sauce
  • 1 tablespoon minced garlic
  • 1 teaspoon kosher salt
  • ½ teaspoon black pepper
  • 4 burger buns

Instructions 

  • Prepare the Mushrooms – Cut off the stems, then use a spoon to scoop out the brown gills. Gently clean any dirt off the surface using a damp paper towel.
  • Score the Tops – Use the tip of a paring knife to cut a ½-inch crosshatch pattern on the tops of the mushroom caps.
  • Make the Marinade – In a small bowl, whisk together olive oil, vinegar, soy sauce, minced garlic, salt, and pepper.
  • Marinate the Mushrooms – Add the mushrooms to a large plastic bag or baking dish. Turn to coat in the marinade and allow to sit for 30 to 60 minutes.
  • Prepare the Grill – Preheat the grill over medium-high heat 350 to 400ºF (177 to 204ºC). Clean and carefully grease the cooking grates with tongs and a paper towel dipped in oil.
  • Grill the Mushrooms – Remove the mushrooms from the marinade and place them on the hot grill, cap-side down. Cover and cook until the mushrooms have released their liquid with charred marks, 4 to 6 minutes. Flip and cook covered for 3 to 5 minutes. If adding cheese, place it on after flipping, then cover and cook until melted.
  • To Serve – Place the grilled portobellos on toasted burger buns and add desired toppings.

Notes

  • Topping Suggestions: Tomatoes, avocado, cheese slices (havarti, sharp cheddar, swiss, pepper jack), mayonnaise, pesto sauce, butter leaf lettuce, roasted red pepper.

Nutrition Facts

Serves: 4 servings
Calories 314kcal (16%)Carbohydrates 28g (9%)Protein 7g (14%)Fat 20g (31%)Saturated Fat 3g (15%)Sodium 1059mg (44%)Potassium 383mg (11%)Fiber 2g (8%)Sugar 7g (8%)Vitamin C 1mg (1%)Calcium 84mg (8%)Iron 2mg (11%)

Percent Daily Values are based on a 2000-calorie diet. All nutritional information is based on estimated third-party calculations. Each recipe and nutritional value will vary depending on the brands you use, measuring methods, and portion sizes per household.

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Jessica Gavin

I'm a culinary school graduate, cookbook author, and a mom who loves croissants! My passion is creating recipes and sharing the science behind cooking to help you gain confidence in the kitchen.

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4.80 from 20 votes (12 ratings without comment)

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12 Comments Leave a comment or review

  1. Jill Zinner says

    Well we tried it tonight! The mushrooms were old ones…I had trouble getting the inside stuff out…the marinade was amazing. I just dove in with trust in you…we did not grill but used air fryer…400 degrees 6 minutes per side…very messy clean up but they were floppy and yummy…so surprised and happy! Next time I will purchase better mushrooms and bring home and use right away…not keeping in fridge for days…I put foil in the bottom pan and the mushrooms on the rack. We have a Ninja that sits on the kitchen counter flips up to the wall so not your standard air fryer…still great…use it all the time… We/I will do this again and GRILL…Thank you I really truly like your ideas and recipes…

    • Jessica Gavin says

      Thank you, Jill! Thanks for sharing your experience making the mushrooms in the air fryer. I’ve been curious about that method!

  2. Lindi says

    The Burger Buns, are they like a broiche bun. What we call a burger bun is a low round flat bun with sesame seeds, the portable with tomato and Spanish onion would be beautifully complimented with the slight sweetness of the broiche.

    • Jessica Gavin says

      Hi Lindi- Yes, I used a brioche-style bun for the recipe, however you can use your favorite kind.

  3. Rosemarie Vernola says

    I don’t have a BBQ grill. Do you think these would taste good if I use a George Foreman electric grill?

    • Jessica Gavin says

      Yes, you can definitely use a George Foreman grill. Check after half of the recommended time since it cooks both sides at the same time. Let me know how it turns out! That grill got me through college!

  4. Niccie Crespin says

    I added some fresh rosemary and horse radish to spice the marinade up a bit. Gave it a little kick. Delicious.

  5. Christine says

    I’ve made portobello burgers before but its the first time I’ve added soy sauce and scored the tops and removed the gills which I think made for a better texture and tenderness of the portobello. I also make a pesto/mayo to spread over the focaccia bread. ‘)

  6. JJ says

    I’ve made this recipe MANY times and we love it so much we’ll get hungry for it, and go pick up some portobellos, or scout them down at the local farmer’s market. LOVE the balsamic vinegar! Nice simple marinade that packs a whollup and wows guests!