WifeSaver Macaroni and Cheese

Not sure if WifeSaver is only local or not but they have a lot of home style cooking. Chicken, shrimp, veggies, etc. Anyway, they have some of the best macaroni and cheese and I’d love to know the recipe. I’ve never made macaroni and cheese from scratch before but I plan on trying tomorrow and I have been searching the recipes to get an idea of the way to put it together. Most all have you cook the milk and cheese and butter 1st. But WifeSaver’s has lumpy cheese, so I do not think they melt it 1st. Any ideas on doing it this way would be greatly appreciated.

Thank you for your time and suggestions in advance.