Heat oil and butter in a 10 inch skillet over medium high heat. Cook onion and garlic for about 5 minutes, stirring occasionally, until tender. Stir in wine and cook uncovered until liquid has evaporated. Stir in whipping cream, asparagus and black pepper. Heat to boiling, reduce heat and simmer for about 30 minutes or until sauce has thickened, stirring frequently. While sauce is simmering, prepare pasta according to package directions. Drain pasta and combine with sauce and 1/4 cup of Parmesan cheese. Toss until pasta is evenly coated. Sprinkle with remaining cheese and serve.