First, peel the cheese, cut it into cubes, put it in a bowl with milk, cover it with plastic wrap and leave it in the refrigerator for at least 8 hours.
Put the bowl back, discard the cheese, and set the milk aside.
Put the cheese in a container suitable for cooking over a double boiler, and stir well with a spoon or spatula until it melts over low heat (actually over a double boiler).
When the cheese is completely melted, add the egg yolks, one at a time. Finally add the cold butter and continue mixing.
Take the 100g of milk you set aside and mix it. You can add more depending on your desired concentration.
Season to taste with nutmeg and pepper.
The Valle d’Aosta fondue is ready. Transfer to a typical Burgundy, heat on the stove to keep it liquid, and serve immediately. Best served with croutons.