This is a delicious sauce made with cream and pork sausage. The town of Norcia in mountainous southeastern Umbria is renowned for its pork products, and it is the source of this simple and delicious recipe. The town is Norcia, and the sauce made in the style of Norcia uses the adjectival form Norcina, with the extra "n".
The recipe calls for fresh Italian pork sausage, but there are many varieties. Try to get a high-quality sweet Italian sausage without fennel, or if you can't get that then use American country-style sausage meat. It doesn't have to be in the casing because you'll be taking it out of the casing before cooking it anyway. For authenticity, you want the flavor to be about the pork, not dominated by fennel or other seasonings.