Thoroughly mix all of the meatball ingredients together in a bowl. Using clean hands roll about 12 x 60g (2 oz.) mince balls and place them into a large earthenware dish. Clingfilm and refrigerate until the sauce is ready.
For the sauce fry the onion and bacon over a medium heat until the onion is soft and the bacon is golden brown. Add the garlic and cook for 1 minute. Add the vegetable stock and bring to the boil, then the chopped tomatoes. Finally stir in the basil and remove from the heat.
Pour over the meatballs and sprinkle the grated parmesan on top. Cover with tin foil and bake in the hot oven for 35 minutes. Remove the foil and cook for a further 10 minutes.