Remove the rind from the Fontina, cut it into thin slices, put it in an oven pan and cover it with milk. Put it in the fridge covered with cling film overnight.
The next day drain the Fontina, but not too much, keep the milk aside and transfer the cheese in a normal or non-stick pan; add the cold butter in small pieces and put it on a pot with boiling water for bain-marie cooking.
Melt the Fontina over medium heat stirring with a wooden spoon; at first a mass will form which will slowly begin to melt and become fluid; at this point add one yolk at a time stirring quickly to mix well before adding the next one.
Sprinkle pepper to taste and, once the yolks have been added, adjust the density of the fondue to taste by adding a little of the well-warmed milk set aside.
When the fondue is ready, place it in the cheese fondue pot with the stove, which will keep it warm and fluid, and serve it with various types of toast, nut bread, grissini, boiled potatoes, slices of pear and apple, broccoli and cauliflower florets, steamed Brussels sprouts and anything else your imagination and personal taste suggest.