In a large skillet, heat 1 tablespoon of olive oil over medium heat. Remove casing from the sausage and crumble it into the pan. Cook for about 5-7 minutes until browned.

Add diced onion and minced garlic to the skillet. Sauté for about 3 minutes until the onion is translucent and fragrant.

Bring a large pot of salted water to a boil. Add pasta and cook according to package instructions until al dente, around 8-10 minutes. Drain pasta, reserving a half cup of pasta water.

Lower heat under the skillet and pour in heavy cream. Stir and simmer for 3-5 minutes until slightly thickened. Add reserved pasta water if too thick.

Add drained pasta into the skillet with sauce. Toss until combined and warmed through. Ensure each piece is coated in the sauce.

Sprinkle crushed red pepper flakes and stir in chopped parsley or basil. Serve immediately while hot.