Kitchens (sub?)level(s) in the megadungeon

Perhaps a kitchen with some related, legendary items and foes in the “larder” that exist there.  The problem is that the entrance from the megadungeon is collapsed or lost for some reason (or blocked from the kitchen side).  It can be accessed from a hidden dumbwaiter in quarters.

This could have some sort of tie-in with The Gourmand.