1. Heat the olive oil in a non-stick frypan over medium heat. Add the meatballs and cook, turning, for 6-8 minutes until golden and cooked through. Add the passata and basil and bring to a simmer, then reduce the heat to low and cook for a further 6-8 minutes until the sauce has thickened and reduced.
2. Preheat grill to high. Place the rolls on a lined baking tray. Divide meatballs and sauce among rolls, top with cheese. Grill for 1 minute or until the cheese starts to melt and rolls warm through. Serve immediately with extra cheese, if you like.