WITH GRILLED CHICKEN, PESTO, AND SUN-DRIED TOMATOES 4 large Portobello mushrooms (approximately 1 pound) Marinade for Mushrooms: 5 tablespoons best-quality olive oil 5 tablespoons best-quality dry sherry Marinade for Chicken: ½ cup best-quality olive oil 2 tablespoons balsamic vinegar 1 teaspoon Dijon mustard 1 garlic clove, pressed 4 skinless, boneless chicken breast halves, each cut in half ¼ cup pesto 2 tablespoons finely chopped sun-dried tomatoes, drained and patted with paper towels if packed in olive oil Carefully clean the mushrooms with a damp paper towel and trim. Remove and chop the stems. Place the mushroom caps, tops down, and the chopped stems in a 9- by 13-inch glass baking dish. Pour 1 tablespoon olive oil and 1 tablespoon sherry over the underside of each mus

