Place the mince, lentils, onion, zucchini, basil, quinoa flakes, garlic, egg and 1 teaspoon of the oregano in a large bowl. Season well with salt and pepper. Use clean hands to mix well until combined. Roll rounded tablespoonfuls of the mixture into balls. Transfer to a lined plate. Cover with plastic wrap and place in the fridge for 30 minutes or until firm.
Preheat oven to 200C/180C fan forced. Heat the oil in a large, non-stick ovenproof frying pan over medium-high heat. Cook meatballs, turning, for 8 minutes or until browned. Remove from heat. Drizzle with tomato passata, keeping meatballs slightly exposed.
Combine tomato and vinegar in a bowl. Season. Spoon the tomato mixture among the meatballs. Sprinkle with mozzarella and feta. Sprinkle with remaining oregano. Bake for 25 minutes or until golden and bubbling. Stand for 5 minutes. Sprinkle with extra basil.
