Cook macaroni according to package directions and drain.
Melt butter in a saucepan over medium heat.
Add flour and stir for about one minute.
Slowly pour in the milk while stirring.
Cook until the sauce begins to thicken.
Add cheddar cheese and stir until completely melted.
Season with salt, pepper, and garlic powder.
Add the cooked macaroni and mix well.
Serve immediately while warm and creamy.