Gnocchi -You can make your own and substitute for the store-bought.
Tomatoes - High-quality tomatoes are essential, or you may have a very acidic sauce. If you can't find pomodorini (cherry tomatoes), use crushed tomatoes or passata (crushed strained tomatoes).
Baking: Preheat the oven to high heat so the mozzarella melts without overcooking the gnocchi.