Pre-heat oven to 350°F. Grease an 8" square glass baking dish and cover bottom with a layer of crumbs. Place a layer of sliced hard boiled eggs, then sprinkle with crumbled bacon if using, dot with a few bits of butter, then repeat this layer process, finishing with a layer of buttered crumbs. Pour cream, milk or half and half over the whole dish until it comes about halfway up the side of the dish. Place in oven until heated and browned, about 4-6 minutes.