Method. Cook macaroni according to the package directions. Drain. Add butter to skillet, as soon as butter melts whisk in flour. Continue whisking until flour is fully mixed with butter. Then cook for about a minute to get rid of the flour taste. Slowly add evaporated milk a little at the time, followed by the half and half ; you do not want the mixture to form any lumps. Simmer for about 3-5 minutes until mixture thickens slightly. Add seasonings, onion and garlic powder, creole seasoning and cayenne pepper. Bring to a simmer and let it simmer gently for about 2 minutes.