Rub the bottom of a flat baking dish with a third of the butter and sprinkle with a third of the crumbs. Arrange a dozen oysters over the crumbs. Sprinkle with salt and pepper and half of the shallots.
Make another layer of crumbs and dot with another third of the butter. Arrange the remaining oysters over this. Add remaining shallots. Sprinkle with a final layer of crumbs. Dot with the remaining butter and sprinkle with the cheese.
Dribble the cream over the casserole. Add just enough so that the casserole is moist but not soupy. Bake for fifteen minutes.