To make meatballs, combine pork mince, 3 cloves crushed garlic, egg, breadcrumbs, parmesan and lemon rind in a large bowl. Season with salt and pepper. Mix until well combined. Using ¼ cup mince mixture per meatball, roll into balls. Place on a tray, cover and refrigerate for 30 minutes.
Preheat oven to 200°C/180°C fan-forced. Heat oil in a large deep oven-proof frying pan over medium heat. Cook meatballs, in batches turning occasionally, for 5 minutes or until evenly browned. Transfer to a plate. Set aside.
Add onion and remaining 2 cloves crushed garlic to pan. Cook, stirring occasionally, over medium heat for 4-5 minutes until tender. Stir in tomato sauce or passata pasta sauce and bring to boil.
Add meatballs to pan. Stir to coat in tomato mixture. Cover and bake for 20 minutes. Uncover, stir and sprinkle with cheese. Bake, uncovered, for 8-10 minutes until cheese melts.
