24 Large mushrooms (1½ - 2 inches wide)

4 tablespoons olive oil

1 large garlic clove, minced

½ cup finely chopped onion

½ cup finely chopped prosciutto (3oz)

¼ cup fine dry bread crumbs

3 tablespoons minced fresh flat-leaf parsley

¾ cup finely grated Parmesan cheese (I shredded)

1 large egg, lightly beaten

¼ teaspoon salt

¼ teaspoon freshly ground black pepper

Put a rack in the middle of oven and preheat oven to 400°F> lightly grease a shallow baking dish large enough to hold mushroom caps in one layer.

Remove stems from mushrooms. Trim and discard bottoms of stems and finely chop stems.

Heat 2 tablespoons of oil in a 10- to 12-inch heavy skillet over moderate heat. Add mushroom stems, garlic, and onion and cook, stirring until stems are very tender, about 8 minutes.

Transfer to a bowl, add prosciutto, bread crumbs, parsley ½ cup Parmesan, egg, salt and pepper and stir to combine well.

Divide filling among mushroom caps, mounding it slightly and arrange in one layer in greased baking dish. Sprinkle mushrooms with remaining ¼ cup parmesan and remaining 2 tablespoons oil.

Bake until mushroom caps are tender, about 20 minutes.