Heat the grill to high. Heat the oil in a large frying pan and squeeze the sausages out of their skins into the pan, breaking up the meat with a wooden spoon or spatula. Fry over a high heat for about 5 minutes until starting to brown. Meanwhile, bring a large pan of salted water to the boil.
Add the chilli flakes, oregano and garlic to the sausage meat, stirring for about 1 minute until fragrant, then stir in the tomatoes, sugar and some seasoning. Simmer for about 5 minutes.
Add the frozen peas to the boiling water and return to the boil, then tip in the gnocchi. Once it comes back to the boil again, the gnocchi will be ready. Drain, reserving a little water.
Tip the gnocchi and peas into the sausage mixture, adding a little of the reserved water if necessary to loosen the sauce. Mix well, then scatter the mozzarella, Parmesan and panko crumbs on top. Grill for 2-3 minutes until bubbling and golden, protecting the pan handle if it isn’t heatproof. Serve with a salad on the side.