Cook the pasta in a large pot of boiling salted water until just tender. While the pasta is cooking, cook the peas in boiling water for only a minute or two. Drain and set aside. Drain the pasta, return it to the pot, and toss it with the butter. Add the peas, prosciutto or ham, and the cream, and toss. Add salt and pepper to taste. Serve piping hot with the grated cheese.