Crostini with Mushrooms, Prochiutto and Blue Cheese Crumbles

This appetizer is so yummy. It is from Bon Appetit Magazine..recipe by Bonnie Wilkins Metully. Reminds me of the ones my aunt makes.
Crostini with Mushrooms, Prochiutto and Bluc Cheese Crumbles:

3 tbsp butter
1/2 pound fresh shiitake mushrooms, stemmed, caps chopped
4 ounces crimini mushrooms, chopped
2 garlic cloves, minced
1/2 cup whipping cream
1/2 cup crumbled blue cheese (about 2oz)
1/2 tablespoons chopped thinly sliced prosciutto (about 2 1/2 ounces)
18 1/2-inch-thick diagonal bread slices cut from 1 sourdough baguette
Chopped fresh parsley
1/2 cup shredded parmesan cheese
1 tbsp olive oil

Preheat oven to 375°F.

Melt butter in heavy large skillet over medium-high heat. Add all mushrooms and garlic and sautè until mushrooms are cooked through and brown, about 10 minutes. Add cream and boil until liquid is completely absorbed, about 2 minutes. Remove from heat. Add blue cheese and stir until cheese melts. Mix in prosciutto. Season to taste with salt and pepper. Transfer mushroom topping to bowl. Do these one day ahead, Mushrooms. Cover and refrigerate.

Arrange bread slices on baking sheet. Brush a small amount of olive oil on each piece and bake until just golden, about 5 minutes. Mound 1 generous tablespoon mushroom topping on each slice and sprinkle a little parmesan cheese over each piece. Return to oven; bake until topping is heated through, about 6 minutes. Sprinkle with chopped parsley and serve warm.