Preheat the oven to 350 degrees F (175 degrees C).
Melt 3 tablespoons of butter in a large skillet over medium heat. Add the mushrooms, and saute until tender, about 10 minutes. Layer half of the mushrooms in the bottom of a casserole dish. Sprinkle with half of the olives, half of the cheese, and 1 tablespoon of flour. Repeat the layers then top with the bread crumbs. Drizzle 2 tablespoons of melted butter over the crumbs.
Bake for 30 minutes in the preheated oven, until bubbly and browned on the top.