Cook rotini in salted boiling water until al dente, then drain and set aside with ½ cup of pasta water reserved.
In a skillet, heat olive oil and butter, season chicken with garlic powder, paprika, salt, and pepper, and cook until golden and done—about 5–7 minutes Remove and set aside.
In the same skillet, melt butter, sauté minced garlic until fragrant, then stir in flour to form a roux.
Gradually whisk in heavy cream and chicken broth, letting it simmer until thickened.
Stir in Parmesan until smooth, then season with salt, pepper, and red pepper flakes if you like.
Add the chicken and rotini, tossing everything in the creamy sauce.
Adjust consistency with pasta water if needed. Finish with fresh parsley and extra Parmesan before serving hot.