Boil the pasta until firm, drain, and set aside. Using the same pot, add the olive oil and butter and melt over medium heat. Stir in garlic and simmer for 20-30 seconds (do not brown the garlic). Stir in flour and whisk for 1 minute, then pour in the milk, chicken broth and whisk until the mixture is bubbling. Add garlic powder, cheese, and parsley. Mix in the pasta. Set aside. In a small pan, fry the sausage slices until done to your liking. Add to the pasta and stir.
Recipe by Thrifty DIY Diva at https://www.thriftydiydiva.com/creamy-garlic-pasta-shells-with-smoked-sausage/