Slice the mozzarella into medium-sized slices of about 5mm (0.2in) thick and lay them on a paper towel in a single layer for at least 30 minutes to dry. Press and pat dry with additional paper towels to ensure the mozzarella is as dry as possible.
If desired, remove the crusts from the sandwich bread.
Carefully arrange a few mozzarella slices on one piece of bread, and place another slice of bread on top.
Cut the sandwich in half diagonally to form two triangle-shaped sandwiches.
Fill one plate with a cup of flour, fill another plate with a cup of breadcrumbs, and in a bowl beat the two eggs with a fork and add a pinch of salt.
Take a triangle sandwich and dip all the sides of the sandwich first in the flour, then in the egg and finally in the breadcrumbs. Tip: use two forks to flip the sandwich in the eggs. After each triangle is fully coated, place it in a baking pan lined with baking paper. Continue until you finished all the triangle sandwiches.
In a medium-sized deep saucepan, pour in an abundant amount of oil and turn on the heat, bring the oil up to temperature, approximately 175 °C / 350 °F. In order to properly fry the sandwiches, the oil should be very hot.Fry each sandwich for 1 minute on each side or until golden brown and crispy. You should only fry one or two triangles at a time to ensure that the oil stays at the proper heat. Fry all the sandwiches.
Place each finished sandwich on a plate lined with one or more paper towels to remove any excess oil. Be sure not to compress or smash the sandwiches, if they still have excess oil you can simply transfer them to a new paper towel. The mozzarella in carrozza sandwiches are best when served warm.