Preheat oven to 375 degrees F. In a buttered gratin or heavy baking dish, layer beets, onions and half of the bread crumbs, dotting each with butter and seasoning each layer with olive oil, Parmesan cheese, Creole seasoning and salt and pepper, to taste. Finish with bread crumb layer on top. Bake, covered, 45 minutes. Uncover and continue baking 15 minutes more, or until top is browned and bubbly. Serve directly from dish.