Saute minced garlic in olive oil, add the sausage (casings removed) and break apart with a fork. Then add red pepper flakes, if using. Add whipping cream, season with salt and pepper.
In the meantime, in a separate pot, boil water, add the pasta and rapini and cook pasta until al dente.
Toss the penne, rapini and sausage together. Garnish with grated parmesan cheese and serve.
Recipe by sprinkles and sauce at https://sprinklesandsauce.com/penne-sausage-rapini/