Grate onion and garlic into a large bowl and then add meat, parsley, mint, oregano, cinnamon, egg, olive oil, salt and pepper and mix well.
Grate potato and squeeze out excess liquid then add to mixture and mix.
Wet hands and take walnut size portions of the mixture and form into oval shapes (for large meatballs) and flatten slightly. For the small meatballs shape them into small balls.
Heat oil in large frying pan, add meatballs and cook for approximately 6 – 8 minutes turning once (cook in small batches).
Remove meatballs from oil using slotted spoon and keep warm.
Serve with tzatziki and quarters of fresh lemon.