Bring large pot of salt water to a boil, cook pasta until al dente (firm to bite, not to soft). Melt butter in a saucepan, add cream, salt and pepper. Heat until steam rises. Toss cheese with cornstarch and add to sauce alon with lemon juice. Stir until mixture is creamy and smooth.
When pasta is done, drain and add to sauce. Toss until evenly mixed, serve with noodles. The sauce may be done in advance and refrigerated then reheated before serving.