Fat on Fat Pasta

A former colleague gave me a recipe similar to this. I since lost it, but I think that this is a close recreation. It's simple, but sooo good.

Ingredients
1 lb sweet Italian sausage, casings removed
1 Tbsn butter
1 Tbsn olive oil
1 medium onion, chopped
4 garlic cloves, minced
1 cup heavy cream
1 tsp salt or to taste
1/4 tsp freshly ground pepper to taste
1 pound Penne pasta, cooked al dente according to package
1 cup freshly grated Parmesan cheese, plus additional for garnish

Method

1. Cook sausage in large skillet over medium-high heat until brown. Use a wooden spoon to break up the sausage while cooking. Remove sausage; set aside.

2. Drain excess grease from skillet; melt butter and oil in skillet; add onion and sauté until softened and golden in color. Add garlic, cook and stir 1 minute.

3. Return cooked sausage to skillet, add cream and simmer until sauce thickens slightly, about 5 minutes.

4. Stir in salt and pepper.

5. Place cooked penne in large serving bowl; pour sauce over pasta; add Parmesan cheese and toss to combine.

Where to eat it?
I haven't found this dish at a restaurant, yet. Most versions in a restaurant use tomato.