Combine mashed potatoes, potato stearch meal, semolina and salt to a smooth paste and form gnocchi.
Sprinkle salmon fillets with olive oil and cook them in oven (150°) for about 15 minutes. Then spice with salt.
Heat oil in a pan, sautee garlic and add tomatoes. Cook all for a short time, add ketchup, boil up and sesaon to taste with salt and pepper. Cut basil into stripes and fold in.
Bring salted water to the boil, add gnocchi and let them simmer for about 2 minutes. Strain gnocchi and stir in butter and parmesan.