1. In a large sauté pan, heat 2 tbsp olive oil. Season the lamb meatballs, add to the pan, and fry until browned all over. Pour off any excess fat and stir through the Passata Rustica and sauce. Bring to a simmer and bubble for 5 minutes, until the meatballs are cooked through and the sauce has thickened.
2. Meanwhile, bring 1 litre of water or vegetable stock to the boil in a saucepan. Pour the polenta into the water or stock and whisk briskly for 1 minute, or as directed in the packet instructions, until thickened. Remove from the heat, stir in Parmesan or Grana Padano and season.
3. Spoon among plates, pour the meatballs and sauce over the top, and garnish with fresh coriander leaves, if you like.