Cook the steak bites by searing them in butter and garlic in a hot pan until browned and cooked through, then remove and set aside.
Prepare the pasta according to package directions, then drain and set aside.
Make the creamy Alfredo sauce by melting butter in the same pan, adding heavy cream, garlic, and Parmesan cheese, then stirring until smooth.
Combine the cooked steak bites, pasta, and Alfredo sauce, mixing everything together until well-coated.
Serve the dish hot, garnished with fresh parsley or extra Parmesan if desired.