Cut the crusts off the white bread slices with a sharp knife. Cut the Mozzarella di Bufala Campana DOP into 4 medium-thick slices and place them on 4 of the bread slices, making sure that they do not spread over the sides, and then cover each with a slice of bread to make a sandwich and press them firmly.
Cut each mozzarella sandwich into two strips. Put the flour onto a plate and beat the three eggs in a bowl with the milk, salt and ground pepper. Dip the strips first in the flour, making sure the sides are well-coated and then in the egg mixture; this will form a seal so that the mozzarella doesn’t leak during frying.
Repeat until you have coated all the strips. Meanwhile heat the oil in a deep skillet and when it is hot, deep-fry the sandwiches until they are golden-brown on all sides.
Then drain the fried sandwiches in a basket or on paper towels.
For the sauce, put extra virgin olive oil in a frying pan, sauté the garlic until golden and then add the San Marzano DOP tomatoes, salt and cook gently.
To serve, place the sauce in a bowl, then the mozzarella sandwiches on the side, just dipping into the sauce, garnish with basil and black pepper and the dish is ready.