Start by cooking your pasta according to package directions, drain, and set aside.
In a large pot melt butter then add in minced garlic. Allow to cook for 1-2 minutes then whisk in flour. Whisk together until flour and butter are combined.
Whisk in chicken broth and half and half. Add salt and pepper and whisk for 5 minutes until thickened. Add Parmesan and 1 cup mozzarella and stir until cheese is melted.
Preheat your oven to 350 degrees F. Add cooked pasta to a casserole dish and pour over homemade warm Alfredo sauce and mix. Slice kielbasa and place it in the casserole dish. I mixed in half of mine and placed the rest on top. Top with remaining mozzarella cheese and sprinkle on parsley. Bake for 10-15 minutes or until cheese is melted and bubbly. Serve and enjoy!