Dice Fontina PDO and remove the rind. Transfer it into a bowl and pour the milk until it is covered. Leave in the fridge overnight.
Separate Fontina PDO from the milk with the help of a strainer.
Put Fontina PDO in a mixing bowl placed on a pan for bain-marie cooking. Melt the cheese over medium heat stirring with a spoon.
When melted, add one egg yolk at a time and continue stirring. Incorporate the cold butter as well. Add pepper to taste.
Add 100 g of the milk kept aside and cook for 30 minutes.
Pour the fondue into the typical fondue pot and serve it with bread morsels