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–+ servings

Grilled Portobello with Basil Mayonnaise Sandwich

A satisfying, meatless sandwich that brings gourmet flavor to everyday lunch. Meaty grilled portobello caps are marinated and seared to perfection, layered with juicy tomatoes, crisp greens, and a fresh, herb-packed basil mayo—all nestled between toasted buns. This Grilled Portobello with Basil Mayonnaise Sandwich is a wholesome, flavor-forward option that’s hearty enough to satisfy vegetarians and meat-lovers alike. Fresh, smoky, and creamy—it’s a garden-inspired twist on the classic burger.
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Prep Time 20 minutes
Cook Time 10 minutes
Additional time 5 minutes
Total Time 35 minutes
Servings: 6
Course: lunch, main dish, sandwish
Cuisine: American
Calories: 412
Ingredients Equipment Method Nutrition Notes

Ingredients
  

  • ⅓ cup balsamic vinegar
  • ¼ cup olive oil
  • 1 tablespoon minced garlic
  • 6 portobello mushroom caps
  • ½ cup mayonnaise
  • 2 tablespoons chopped fresh basil
  • 1 tablespoon Dijon mustard
  • 1 teaspoon lemon juice
  • 6 kaiser rolls split, toasted
  • 1 tablespoon butter softened, or as needed
  • 6 leaves lettuce
  • 6 tomato slices

Equipment

  • Mixing bowls
  • Knife and cutting board
  • Tongs or spatula
  • Small food processor or blender (for basil mayo)
  • Grill pan or outdoor grill

Method
 

  1. Preheat an outdoor grill for medium heat and lightly oil the grate.
  2. Whisk vinegar, oil, and garlic together in a small bowl.
  3. Arrange mushrooms on a baking sheet with the gills facing up; brush with about 2/3 of the marinade and let sit for 3 to 5 minutes.
  4. Transfer mushrooms to the preheated grill with the gills facing down; grill, basting occasionally with remaining marinade, until tender, about 4 minutes per side.
  5. While the mushrooms are cooking, mix mayonnaise, basil, Dijon, and lemon juice together in a small bowl. Butter toasted rolls, then spread with mayonnaise mixture.
  6. Remove mushrooms from the grill and place on bottom buns. Top with lettuce, tomatoes, and top buns.

Nutrition

Calories: 412kcalCarbohydrates: 36gProtein: 8gFat: 28gSaturated Fat: 5gCholesterol: 12mgSodium: 417mgPotassium: 919mgFiber: 4gSugar: 8gVitamin C: 19mgCalcium: 73mgIron: 3mg

Notes

Earthy grilled mushrooms and vibrant basil mayo come together for a vegetarian sandwich that’s anything but boring.

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