Eggs Lyonnaise

6 eggs
1 onion
2 level tablespoonfuls of butter
2 level tablespoonfuls of flour
1/2 pint of milk
1/2 teaspoonful of salt
1 dash of pepper

Hard-boil the eggs, remove the shells, throw them in cold water. Cut the onion into thin slices; put it, with the butter, into a saucepan, shake until the onion is tender, then add the flour, milk and seasoning; stir until boiling. At serving time cut the eggs into slices crosswise, put them in a shallow baking dish, cover with cream sauce and run in the oven just a moment until they are very hot.