1 Pat the mozzarella dry with kitchen towel.
2 Place the flour, beaten egg and breadcrumbs in separate shallow bowls.
3 Lightly roll the mozzarella pieces in the flour, dip in the egg, and then roll in the breadcrumbs.
4 Double-crumb the cheese by dipping in the egg and rolling in the breadcrumbs a second time. The cheese should be completely coated with breadcrumbs so it does not leak out during cooking. Repeat with the remaining cheese.
5 Heat the oil in a a deep-fryer to 180°C (350°F). When hot, fry the mozzarella ball for 1–2 minutes, turning frequently, until golden.
6 To create the tomato sauce, finely chop the onions and add to a frying pan with all other ingredients.
7 Use a potato masher to break up the tomatoes. Bring the sauce to the boil and then lower heat allowing it to bubble rapidly.
8 Cook for 9 minutes until onions are softened.
9 Drain the mozzarella ball on kitchen towel and allow to cool a little before serving.
10 Serve, scattered with a little salt, on their own or with the spicy tomato sauce for dipping.