Cook the onions in the butter. When they begin to brown, sprinkle them with flour. Cook for a minute then add the milk all at once. Bring to a boil, stirring. Add salt, pepper and nutmeg. Preheat the oven to 400F. Slice the eggs and place in an ovenproof gratin dish. Add the grated GruyÅre to the onion sauce and spoon over the eggs. Dot with butter and bake for 20 minutes or so, until golden. As a variation you need not add the GruyÅre to the sauce, sprinkle on just before serving.
