Soften the bread slices into the milk.
Combine meat, eggs, chopped parsley and bread, squeezed into small pieces, in a bowl. Add salt and pepper. Knead the mixture well until it is homogeneous.
Dice Fontina PDO, remove the rind, and keep it aside.
Make the small patties by taking a spoonful of dough, place a cube of Fontina PDO in the middle, and close well.
Make the patties until there is no more dough.
Brown the meatballs in a non-stick pan with a little oil for 15 minutes. Add the tomato puree, basil leaves, salt, and pepper to taste. Cook for another 20 minutes. Serve immediately and garnish with fresh basil leaves.