Clean the leek and slice it into rings. Blanch the tomatoes in boiling water, once peeled and deseeded, drain them and chop them coarsely. Clean and chop the smooth dogfish into chunks; rinse and chop the basil.Trim the French beans, rinse and blanch them in boiling salted water. Drain them and set aside. Heat a the oil in a pan, add the leek, the French beans and after frying for a minute add the dogfish.Fry for 2-3 minutes, fold in the chopped tomatoes, season with salt and pepper and simmer for 2-3 minutes. In the meanwhile cook the pasta in plenty of salted water, add the dogfish ragù and a bit of basil. Ready to serve.