Preheat the oven to 200°C. Grease a baking sheet with non-stick spray.
1. Meatballs: Mix the ingredients well in a large mixing bowl. Shape into balls the size of tennis balls and arrange on a plate. Cover with cling-film and chill in the fridge for at least 30 minutes.
2. Sauce: Heat the oil in a saucepan and fry the onion, celery and bay leaves for a minute. Add the tomatoes and lightly bruise using a wooden spoon. Turn the temperature down and simmer slowly for 10 minutes. Season with the sugar, salt and freshly ground pepper.