Preheat oven to 180°C (160°C fan forced). Heat 1 tablespoon olive oil in frying pan and saute mushrooms and garlic over medium heat for 10-12 minutes or until mushrooms are very soft and well cooked through

In a mixing bowl, combine the mushrooms with oats, ricotta, egg, 50g (1/4 cup) crumbled feta and parsley and season to taste. Shape mushroom mixture into balls and place on a baking tray lined with paper. Bake 20 minutes or until firm and browned

Heat 1 tablespoon oil in a large frying pan over medium heat. Add onion and cook for 5 minutes or until softened. Add tomato paste and cook for one minute then add tomato passata and 1/2 cup of water, simmer for 5 minutes or until slightly reduced. Add the meatballs and simmer for two minutes or until heated through

Serve meatballs sprinkled with remaining feta and extra parsley and serve with spaghetti, steamed greens or mashed potato