Preparation :
Preheat the oven to 180°C.
Peel the hard-boiled eggs and cut them in half. Place them in a buttered baking dish.
In a saucepan, melt the butter over low heat. Add the flour and mix well to form a roux. Cook for 1 to 2 minutes.
Gradually pour in the milk while whisking to avoid lumps. Continue stirring until thickened.
Season with salt, pepper and nutmeg. Remove from heat and stir in half of the grated cheese.
Pour the béchamel sauce over the eggs, then sprinkle with the remaining cheese.
Bake for 20 minutes, until the gratin is golden brown.
Serve hot with a green salad or fresh bread!
