Grilled Portobello Burgers

Adapted from epicurious.com

1/2 cup mayonnaise

2 teaspoons grainy Dijon mustard

6 teaspoons minced fresh rosemary, divided

1 garlic clove, minced

Nonstick vegetable oil spray

4 large portobello mushrooms, stems trimmed

2 tablespoons olive oil

Pinch of salt, pepper, and Montreal Steak Seasoning

4 brioche buns, toasted

Boston lettuce

Mix mayonnaise, mustard, 2 teaspoons rosemary, and garlic in small bowl.

Spray grill rack with nonstick spray, then prepare barbecue (medium heat). Brush mushrooms all over with olive oil. Sprinkle each with 1 teaspoon rosemary, salt, pepper, and Montreal Steak Seasoning. Grill until tender, about 10 minutes per side.