First remove the casing from the sausages and crumble them, then brown them in a non-stick saucepan with onion and oil, finally (when the onion is well dried) blend with the cognac.
Add the puree and reduce for about 15 minutes over low heat, then add the cream and chopped parsley and add salt.
Meanwhile, cook the pasta in a large pot filled with lightly salted boiling water.
Drain the pasta al dente and add it to the sauce, stirring with pecorino, chilli and a little more parsley.