Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   3      tablespoons   balsamic vinegar
   3                    garlic cloves -- minced
   1 1/2  teaspoons     minced fresh thyme leaves
                        OR 1/2 teaspoon -- crumbled
                        dried
     1/2  cup           olive oil
   1 1/2  pounds        portabella mushrooms -- stems
                        - discarded
  18                    arugula leaves -- trimmed,
                        - washed
                        thoroughly -- and spun dry
                        - -- (18 to 24)
   6                    parmesan crisps -- (recipe
                        - follows) as an
                        accompaniment

Preparation:

In a small bowl whisk together vinegar, garlic, and thyme, and salt and pepper to taste. Whisk in oil in a stream, whisking until dressing is emulsified. In a large resealable plastic bag drizzle dressing over mushrooms and seal. Marinate mushrooms at room temperature, turning bag once or twice, 1 hour. Heat a well-seasoned ridged grill pan over moderately high heat until hot a grill mushrooms in batches, covered, 2 to 3 minutes on each side, or until tender. Transfer mushrooms as cooked to a platter and keep warm, covered with foil. Divide arugula among 6 plates. Slice mushrooms thin and serve with arugula and Parmesan crisps. PARMESAN CRISPS Can be prepared in 45 minutes or less. 3/4 cup finely shredded Parmesan cheese 1 1/2 teaspoons all-purpose flour Preheat oven to 350F and line a lightly greased baking sheet with parchment paper. In a small bowl stir together Parmesan and flour. On prepared baking sheet spoon level tablespoons of mixture in mounds 4 inches apart and spread gently into 3 1/2-inch-long ovals. Bake crisps in middle of oven until golden, 8 to 10 minutes. Cool crisps completely on baking sheet and remove carefully with a metal spatula. Crisps may be made 2 days in advance and kept between layers of wax paper in an airtight container at room temperature. Makes about 9 crisps.