Generously butter the soufflé mold, store in refrigerator while preparing the recipe, to harden the butter.
Preheat oven to 400 ° F. Melt the butter in a saucepan over medium heat, add flour and mix with a wooden spoon. Stir in the milk, without lumps, then remove from heat and let cool, stirring occasionally to prevent forming a skin.
Partially peel the maroilles (feel free to leave a little crust to add more character to your recipe). Then cut into cubes. Add them to the sauce. Mix.
Break the eggs, separating the yolks from the whites. Add yolks, one by one, to the butter-flour mixture. Add pepper and nutmeg. Beat the egg whites with a pinch of salt until stiff. Stir carefully.
Pour into soufflé dish and bake immediately for about 20 minutes. Serve right out of the oven.