| Preheat oven to 375°F |
| Pull the stems from the mushrooms and chop the stems fine |
| Oil a rimmed baking sheet |
| 2 Tbsp unsalted butter | sauté 5 min until soft and dry | stir in off heat | mound into caps, set on sheet | drizzle over | bake 375°F 20 to 25 min until tender and golden |
| stems from the caps below mushroom stems, finely chopped |
| 1/2 cup onion, finely chopped |
| 2 cloves garlic, minced |
| 1/2 cup dry breadcrumbs |
| 1/2 cup Parmesan cheese, grated |
| 2 Tbsp fresh parsley, chopped |
| 1/4 tsp salt |
| 1/8 tsp ground black pepper |
| 20 large (about 1 lb) white mushroom caps |
| 2 Tbsp olive oil |