Mac and cheese is always my go to - but some other ideas that come to mind …
High end nachos (made some for dinner watching football on Sunday, better cheese would have been awesome)
Frico (not sure it would work with aged cheddar but worth a try)
You mentioned grilled cheese - love grilled cheese - could make a mornay sauce and do an American croque monsieur - and just read a review for a lobster grilled cheese with chives and cheddar I think it was. I’d try it.
Apples are is season, how about with an apple pie
And along those lines - cheddar biscuits would be great, could use for breakfast too.
Chopped up with herbs and veggies as a stuffing for chicken…
Beer cheese soup - not as horrible as it sounds if you like heavier soups.
