Prepare the leeks, washing them and cooking them either in water or in steam heat for about 15 min.
Drain the leeks well and wrap them in the slices of smoked bacon. Place each wrap into a baking dish.
Prepare the sauce: melt the butter and stirring well, add the flour. Add the milk and let it boil for 5 or 6 min while stirring constantly. Season to taste with salt, pepper and nutmeg and add ¾ of the Pont l’Evêque.
Cover the leek and bacon wraps with the sauce and place thin slices of the remaining cheese on top. Let the dish bake in the oven for about 20 min.