Can you just microwave it? I’m pretty sure that most mac and cheese mixes allow for microwaving nowadays. And you don’t have to buy the special microwave cups, just buy the box mix. I think they stopped printing the microwave instructions on the boxes a number of years ago because they want you to pay more for the special little cups, but if you Google it, you should still be able to find the directions.
Anyway, I wouldn’t use a Crock-Pot or an electric fry pan to make macaroni and cheese.
In fact, here you go…
https://www.tsbvi.edu/independent-living-library/recipes/kraft-macaroni-and-cheese-three-cheese