Keep the mozzarella at room temperature for about ten minutes and try to drain the excess water.
Slice the bread into 1 cm thick slices and cut out 12 circles with a glass, trying to remove the crust. Slice the mozzarella into 1 cm thick slices and sandwich every mozzarella slice between two bread slices. Keep it close with a toothpick.
Flour the bread, then pass every sandwich into an egg wash, then deep fry them for a few minutes until golden on both sides.
Remove the bread from the oil, place it on a plate with come paper towels to absorb the excess oil, sprinkle with sea salt and serve immediately.