Grilled Portobello with Basil Mayonnaise Sandwich

Ingredients

• 0.33 cups balsamic vinegar
• 0.25 cups olive oil
• 1 tablespoon minced garlic
• 6 portobellos mushroom caps
• 0.5 cups mayonnaise
• 2 tablespoons chopped fresh basil
• 1 tablespoon Dijon mustard
• 1 teaspoon lemon juice
• 6 kaisers rolls , split, toasted
• 1 tablespoon butter , softened, or as needed
• 6 leaves lettuce
• 6 tomatos slices

Instructions

1. 1

   Preheat an outdoor grill for medium heat and lightly oil the grate.

2. 2

   Whisk vinegar, oil, and garlic together in a small bowl.

3. 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. 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. 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. 6

   Remove mushrooms from the grill and place on bottom buns. Top with lettuce, tomatoes, and top buns.