Melt butter with oil in heavy large skillet over medium-high heat. Add onion and garlic and sauté until golden brown and tender, about 7 minutes. Add sausage and sauté until golden brown and cooked through, breaking up with back of spoon, about 7 minutes. Drain any excess dripping from skillet. Add wine to skillet and boil until almost all liquid evaporates, about 2 minutes. Add tomatoes with juices and simmer
3 minutes. Add cream and simmer until sauce thickens slightly, about 5 minutes. Stir in 4 tablespoons parsley. Season to taste with salt and pepper. Remove from heat. (Sauce can be prepared 1 day ahead. Cover and refrigerate.)
Cook pasta in large pot of boiling salted water until tender but still firm to bite. Drain pasta; transfer to large bowl.
Bring sauce to simmer. Pour sauce over pasta. Add ¾ cup cheese and toss to coat. Sprinkle with remaining ¼ cup cheese and 2 tablespoons parsley