Any recipes or tips for make ahead Mac and cheese for a party?

My almost 4 year old loves it, particularly Annie's shells and cheese. She also likes when I make it homemade but definitely prefers the box. For her birthday party coming up in July, I would like to have it for her and the other kids, but don't want to make a big batch in the middle of the party.when I've tried reheating it it usually comes out gummy. I know I could make a big tray of homemade ahead of time and bake it during the party but I'd also rather not heat the house up for an hour in July.

Has anyone had success with a recipe that tastes like Annie's and could be microwaved well or maybe keeps in a slow cooker or something?

I bought some in the grocery store prepared food section and she didn't even finish her serving. 😥