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The Best Grilled Portobello Mushroom Burger Recipe

The Best Grilled Portobello Mushroom Burger

Meaty portobello mushroom caps are marinated in a savory balsamic-garlic mixture, grilled until tender and lightly charred, then served on toasted buns with fresh toppings. This recipe makes four flavorful burgers in about 40–55 minutes.
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Prep Time 15 minutes
Cook Time 10 minutes
Total Time 45 minutes
Servings: 4 servings
Ingredients Method Notes

Ingredients
  

Mushroom Burgers
  • 4 caps Large portobello mushroom caps, about 4–5 inches wide
  • 4 buns Hamburger buns
  • 1 tablespoon Olive oil, for brushing or oiling the grill
Marinade
  • 1/4 cup Balsamic vinegar
  • 2 tablespoons Olive oil
  • 1 tablespoon Soy sauce or tamari
  • 2 cloves Garlic cloves, minced
  • 1 teaspoon Italian seasoning or dried oregano
  • 1/2 teaspoon Kosher salt
  • 1/4 teaspoon Freshly ground black pepper
Toppings
  • 4 leaves Lettuce leaves
  • 4 slices Tomato slices
  • 1/4 small onion Small red onion, thinly sliced
  • 4 slices, optional Provolone, mozzarella, or cheddar
  • To taste Mayonnaise, garlic aioli, pesto, or additional balsamic glaze

Method
 

Step-by-Step
  1. Wipe the portobello caps clean with a damp towel. Remove the stems and, if desired, scrape out the dark gills with a spoon to reduce excess moisture and create a cleaner texture.
  2. Whisk the balsamic vinegar, olive oil, soy sauce or tamari, minced garlic, Italian seasoning, kosher salt, and black pepper in a shallow dish. Add the mushrooms and turn them several times so every surface is coated.
  3. Marinate the mushroom caps for 20–30 minutes, turning them once or twice. Do not marinate them for several hours, because the caps can become overly soft.
  4. Preheat a grill to medium-high heat, approximately 400–450°F (200–230°C). Clean the grates and lightly oil them with the remaining tablespoon of olive oil.
  5. Grill the mushrooms cap-side down first for about 4–5 minutes per side. Brush with additional marinade while turning, but do not press the caps; they are ready when tender, browned, and lightly charred.
  6. If using cheese, place one slice on each mushroom during the final minute of grilling and close the lid so the cheese melts. Toast the buns cut-side down for 30–60 seconds.
  7. Spread the preferred sauce over the toasted buns and build each burger with lettuce, a grilled mushroom cap, tomato, red onion, and melted cheese if using. Serve immediately while the mushrooms are hot and juicy.

Notes

Avoid pressing the mushrooms while grilling, since doing so forces out their juices. Marinate for 20–30 minutes rather than overnight, oil the grates well, and toast the buns to prevent sogginess. For a vegan version, use tamari and vegan cheese or omit the cheese.