Grilled Portobello Mushroom Feast Burger

dinner lunch
Prep time 25 mins
cook time 10mins

These hearty burgers will please vegetarians and carnivores alike. Topped with mozzarella, tomato, spinach, and garlic aioli, these burgers are perfect for summer. Serve with a simple saladpasta salad, or homemade chips.



  • 8 large portobello mushrooms
  • ½ cup balsamic vinegar
  • 3 tablespoons Worcestershire sauce
  • 2 tablespoons (plus 2 tablespoons) olive oil
  • ⅛ teaspoon cayenne pepper
  • salt and pepper
  • 4 hamburger buns


  • 8 slices of mozzarella (or preferred cheese)
  • 2 cups spinach
  • 1 large tomato, sliced
  • garlic aioli

Garlic Aioli

  • ½ cup mayonnaise
  • ¼ teaspoon salt
  • 1 teaspoon lemon juice
  • 2 tablespoons olive oil
  • 1 tablespoon garlic, minced
  • ¼ teaspoon paprika


  1. Gently wash mushrooms with a damp cloth and paper towel, remove stems and discard. 
  2. Combine balsamic vinegar, Worcestershire sauce, olive oil, and cayenne pepper in a sealable plastic bag or bowl. Add mushroom caps and refrigerate for 10 minutes.
  3. While the BBQ or grill pan is heating, combine aioli ingredients in a small bowl and set aside.
  4.  Remove the mushroom caps from the marinade and pat dry with paper towels to remove excess moisture, season with salt and pepper.
  5.  Oil the grill and grill the mushroom caps for 4 minutes per side. Add mozzarella for the last 1-2 minutes.   
  6.  Remove the mushrooms from the grill. Brush the buns with remaining olive oil and grill for 1 minute.
  7.  Assemble the burgers. Bun, aioli, spinach, mushroom x 2, spinach, tomato, aioli, bun.