Ingredients4 medium portabella mushrooms
2 tablespoons butter
2 teaspoons minced garlic
2 tablespoons balsamic vinegar
1/4 teaspoon salt
1/8 teaspoon ground black pepper
1 tablespoon chopped fresh basil or parsley
Directions1. Prepare outdoor grill, placing grill rack 5 inches from heat source, or preheat broiler. Separate mushroom caps from stems; set caps aside. Coarsely chop stems to measure 1 cup.
2. In a medium saucepan, melt butter. Add chopped stems and garlic; cook, stirring frequently, until stems are tender, about 5 to 6 minutes. Stir in vinegar, salt and pepper; remove from heat. Transfer to the bowl of a food processor fitted with a metal blade; process until finely chopped; set aside.
3. Place mushroom caps, rounded side up, on grill or broiler pan. Grill or broil 5 inches from heat until mushrooms are hot, about 3 minutes. Turn; spread each mushroom with 1/4 of the chopped mushroom stem mixture; cook until mushrooms are tender, about 4 to 5 minutes longer.
If desired, serve the portabellas on toasted rolls with sliced tomato and arugula or watercress.