Cremini Mushrooms Stuffed with Spanish Ham

I made this recipe once for a work gathering David hosted. They were a huge hit and tasted much better than I expected. I haven't had the opportunity to make them again since as its good adult fare but not a huge hit with picky teenagers.

42 fresh cremini or white button mushrooms, each 2-3 inches in diameter, brushed clean
2 Tbsp fresh bread crumbs
2 Tbsp chopped, fresh flat-leaf parsley
1 tsp minced fresh sage
1 large garlic clove, finely chopped
3 oz serrano ham or prosciutto, finely chopped
3 Tbsp sour cream
1/2 tsp salt
1/4 tsp fresh ground pepper
2 Tbsp dry white wine or substitute
2 Tbsp grated Parmigiano-Reggiano cheese

Preheat oven to 400. Lightly oil 1 heavy baking dish or 2 large enough to accommodate the mushrooms snugly in a single layer. Trim off the rough base of each mushroom stem, then remove the stems and chop finely. In a large bowl, combine the chopped stems, the bread crumbs, parsley, sage, garlic, ham, sour cream, salt and pepper. Mix together thoroughly. The mixture should hold together in clumps. If it seems dry, mix in another 1-2 tsp sour cream. Put the mushroom caps, stem sides up, in a steamer basket set over simmering water. Cover and steam until tender and glossy, about 3 minutes. Lift out the basket, allowing any moisture to drain, and let cool. Spoon 1 generous tsp of the ham mixture onto the stem side of each mushroom cap and smooth it into an even, rounded mound. Place the mushrooms, stuffing side up, in the prepared baking dish. Drizzle the wine around the edges of the dish and sprinkle each cap with about 1/8 tsp of cheese. Bake, uncovered, until golden, about 30 minutes. Let cool for 5 minutes, garnish with cheese and serve warm or at room temperature. Makes 42 bites.

Make ahead tip: the steamed mushrooms and stuffing can be stored separately in the refrigerator for up to 24 hours before stuffing.