Crush the garlic in a pestle and mortar, with some salt. In a large bowl, mix all the ingredients together (except for the olive oil and flour), and put the mixture in the fridge for two hours. Then make into meatballs, covering each one with a little flour. Fry the meatballs in hot oil and place them on absorbent paper, while you prepare the sauce.
For the tomato sauce, steam the onion in 1 cup water until it softens. when the water evaporated, add the oil and garlic and sautee lightly. Add the parsley, chopped tomato, allspice, a little sugar, and a little hot water.
Bring the sauce to a boil, and add the meatballs and olives to it, taking care to cover them with sauce. Simmer until the sauce is thick.
Serve with potatoes, rice, or pasta, or on its own, as a delicious mezze.