Cook the pasta according to package directions, drain and set aside.
Heat olive oil and butter over medium-high heat in a skillet; Add the onion and saute until it begins to caramelize (10-15 mins)
Add sausage to the onion mixture and crushed red pepper if desired. Continue cooking until sausage is cooked through. Add the garlic and continue cooking for another couple of minutes. Drain excess fat.
Add chicken broth and bring to a boil then cook down a few minutes until broth has significantly reduced.
Add the can of undrained tomatoes, bring to a boil and reduce heat to a medium simmer. Continue cooking for another 2-3 minutes. Add the heavy cream, bring to a boil, reduce heat to medium simmer and cook for about 5 more minutes.
Turn down to low, add the drained pasta and parmesan cheese to the sauce. Mix well.
Add the basil or parsley, salt, pepper. Adjust seasonings as desired. Sprinkle with parmesan cheese before serving.