Place the gnocchi into the base of an ovenproof dish directly from the pack.
In a frying pan over a medium heat, warm a little oil and add the onions and peppers and cook and stir until soft, roughly 5 minutes. Add the tomatoes, chilli flakes and salt and leave to simmer for 5 minutes. Pour the sauce over the gnocchi and mix together. Lay the slices of mozzarella on top.
Bake in the preheated oven for around 20 minutes or until the cheese is bubbling and is golden in colour. Remove from the oven and serve.