1 tablespoon butter
1 tablespoon olive oil
1 medium onion, thinly sliced
3 garlic cloves, minced
1 pound sweet Italian sausage, casings removed
1 cup dry white wine
1 14-ounce can diced peeled tomatoes with juices
1 cup whipping cream
6 tablespoons chopped Italian parsley
1 pound penne pasta
1 cup freshly grated Parmesan cheese
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 drippings from skillet. Add wine to skillet and boil until almost all liquid evaporates, about 5 minutes. Add tomatoes with juices and simmer 5 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 1/2 cup cheese and toss to coat. Sprinkle with remaining 1/2 cup cheese and 2 tablespoons parsley.