Bring large pot of water to a boil.
In skillet, heat oil over medium-high heat. Add onion and sausage; cook, stirring often, until sausage is no longer pink, 8 minutes. Remove skillet from heat. Add brandy and wine; cook 2 minutes. Add cream, salt, pepper, pepper flakes; simmer, stirring occasionally, for 5 minutes.
Cook fettuccine in boiling water until done; drain. Stir cheeses, basil into sausage sauce. Toss with pasta. Makes 8 servings.