combine the beef, onion, carrot, zucchini, tomato sauce, barbecue sauce, cheddar and flour into a medium bowl and use your hands to combine.
roll tablespoonfuls of the mixture into balls and place on an oven tray. Place the breadcrumbs on a plate. Roll each meatball in breadcrumbs to lightly coat. Cover with plastic wrap and place in the fridge for 30 minutes or until firm.
heat the oil in a large non-stick frying pan over medium heat. Add half the meatballs and cook, turning occasionally, for 5-7 minutes or until golden brown and cooked through. Transfer to a plate lined with paper towel. Repeat with remaining meatballs. Serve immediately