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Portobello Burger with Thousand Island Sauce Recipe

This Portobello Burger with Thousand Island Sauce is a satisfying, flavorful alternative to traditional burgers. Juicy, meaty portobello mushrooms are marinated and grilled to perfection, then topped with a creamy, tangy Thousand Island sauce. Perfect for vegetarians or anyone looking for a lighter yet indulgent burger option!
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Equipment

  • Grill or grill pan
  • Mixing bowls
  • Basting brush
  • Small whisk or fork

Ingredients
  

  • For the Portobello Burgers:
  • 4 large portobello mushroom caps
  • 3 tablespoons olive oil
  • 2 tablespoons balsamic vinegar
  • 1 teaspoon soy sauce
  • 1/2 teaspoon garlic powder
  • 1/2 teaspoon smoked paprika
  • Salt and black pepper to taste
  • 4 burger buns toasted
  • Lettuce tomato slices, and red onion (for toppings)
  • For the Thousand Island Sauce:
  • 1/3 cup mayonnaise
  • 2 tablespoons ketchup
  • 1 tablespoon sweet pickle relish
  • 1 teaspoon white vinegar
  • 1/4 teaspoon onion powder
  • Salt and black pepper to taste

Instructions
 

  • Prepare the Mushrooms:
  • Gently clean the portobello mushroom caps with a damp paper towel. Remove the stems and scrape out the gills with a spoon if desired (optional for a cleaner look and milder flavor).
  • Make the Marinade:
  • In a bowl, whisk together olive oil, balsamic vinegar, soy sauce, garlic powder, smoked paprika, salt, and pepper. Brush the mixture generously onto both sides of the mushroom caps.
  • Grill the Mushrooms:
  • Preheat your grill or grill pan to medium heat. Grill the mushrooms for 4-5 minutes per side until tender and slightly charred.
  • Prepare the Thousand Island Sauce:
  • In a small bowl, mix mayonnaise, ketchup, sweet pickle relish, white vinegar, onion powder, salt, and pepper. Stir until smooth and set aside.
  • Assemble the Burgers:
  • Place each grilled portobello mushroom cap on the bottom half of a toasted bun. Add lettuce, tomato slices, and red onion as desired. Generously spread Thousand Island sauce on the top half of the bun, then assemble the burger.
  • Serve:
  • Serve the burgers immediately with your favorite sides like fries, sweet potato wedges, or a fresh salad.