In a bowl, beat the egg and add the salt, pepper and chilli flakes (if using).
On a plate, combine the breadcrumbs and parsley.
One at a time, dip the mozzarella cheese in the egg and then roll in the breadcrumbs. Carefully add to the oil and deep fry for around 4 to 5 minutes until golden brown. Remove from the oil and place on kitchen paper to drain. Serve.