Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Cut sausage into slices. Heat 2 tablespoons of oil in a large pan. Fry the sausage and gnocchi for 4-5 minutes one after the other until golden brown.
In the meantime clean and wash the spring onions and cut them into fine rings. Put the gnocchi and sausage in an ovenproof dish.
Sauté onions and 1 teaspoon curry in the frying fat. Add ketchup and 1⁄8 l water, bring to the boil. Season with salt and pepper. Pour sauce over the gnocchi, sprinkle with cheese. Bake in a hot oven for about 15 minutes.