How To make Lumache Con Mascarpone E Noci(Shells with Cheese and Nuts)

1/2 lb Pasta shells
3 tb Butter
3/4 c Mascarpone cheese
3 tb Parmesan cheese
1/3 c Walnuts -- toasted/fine chop
Cook pasta to the aldente stage; drain. Melt butter in a fireproof serving dish. Add the mascarpone cheese (or whipping cream) but do not let boil. Add cooked pasta to the warm mascarpone mixture, coating it well. Add the parmesan cheese and chopped walnuts. Serve with extra parmesan to taste. This is a very rich dish and a little goes a long way. Prep time 15 mins, Cook time 15 mins.