Cooking time and temperature for one oven and two different dishes
Heat ham at 275.
Remove ham and hold. Covered with foil and maybe towels to hold heat.
Raise oven temp, bake mac &amp; cheese.
Ham should still be warm when mac and cheese done.


If it were me, I'd return the ham to the oven for the last fifteen minutes or so to crisp the skin a bit with the higher temperature.