Cut the top part of the mozzarella, so that it forms a "door." Be sure not to cut it completely off! Carefully holding the "door" open, spoon out some cheese to make room for the ingredients.
Add a bit of ham, tomato, and basil to the mozzarella, and then close the top part.
Now roll each ball in flour, then in egg, and finally in breadcrumbs.
Fry each ball in a pot of vegetable oil for about six minutes.