Put the sausages in a frying pan and cover with water.
Bring to the boil, then simmer until the water evaporates.
Cool, remove the meat from the casings and crumble.
Fry the onion and fennel in the oil until soft.
Add the sausage, wine and passata or tomato sauce. Cook for 10 minutes.
Add the basil and season with salt and pepper.
Cook the penne in lightly salted boiling water until al dente, then drain.
Stir in the sauce.Put 1 tablespoon ricotta on each plate.
Spoon the pasta over the top, and sprinkle with Parmesan.