Shell the cauliflower and cut it into small florets. Cook it in boiling salted water until it has softened.
Dice Fontina PDO removing the rind. Place it in a bowl and pour the milk until it is covered. Leave it in the fridge overnight.
Heat the butter in a saucepan; add Fontina PDO and 150 ml of milk. When the mixture begins to melt, add the egg yolks one at a time while continuing to stir.
Transfer the cauliflower tops into previously buttered bowls, sprinkle with fondue and a grind of black pepper and bake in the oven at 180°C for 10 minutes.