For the polenta, bring the stock to a boil in a medium saucepan. Reduce heat to low and slowly add the polenta while whisking vigorously to prevent lumps. Season with salt.
Cover and simmer for about 20 minutes, stirring occasionally, until cooked. Stir through the butter and pecorino.
Meanwhile, heat a splash of oil in a large frying pan on medium high. Squeeze bite size meatballs out of the sausage casings and fry for about 5 minutes or until cooked. Keep aside.
Add another splash of oil and sauté the onion and mushrooms in the same pan for 5 minutes. Season with salt and pepper. Return the meatballs and cook until heated through.
Combine the avocado with a splash of oil, chives and garlic. Serve the polenta with the avo, meatball mixture and extra pecorino.
