A hugely popular favorite in the southwest are Christmas tamales. If you can find a quality source. I don’t recommend making them yourself because they are an art form.
Once made, wrapped in the corn husks and steamed, they can be wrapped in parchment and put in a sterno-steam-tray. They are great right out of the husk, and you can provide warmed red and green enchilada sauce for anyone who wants to pour it on top.
However, for 25 people you are going to need three or more large trays. People do tend to hog on them.
Beef, pork, chicken, it is a very versatile treat.
I live in a little ‘barrio” and I see the ladies buying stuff for tamales at holiday times. The little ethnic store across the street sells everything one needs - corn husks, pots for steaming, masa, etc.
Can you give us a recipe? I like to make things by hand.
=JT