Depends -
Cold I make Russian Potato Salad.
Hot I make one of several different things:
Crock Pot Pierogies - layer cooked lasagna noodles, sauteed shredded cabbage, mashed potatoes, onions sauteed in butter several layers deep, ending with sauteed onions.
Crock Pot Beef Bourguinon - more or less the Julia Child recipe.
Desserts - I make baklava either tree nut or peanut version. [I have a friend who is allergic to tree nuts, so I made her a peanut version that ended up being surprisingly popular]
When I was doing a meal for about 40 assorted people, I provided kosher vegan ‘minestrone’ [virgin 5 gallon pot, knife, cutting board and ladle. Homemade from assorted dried beans, onions, garlic, fresh tomatoes, herbs, salt, pepper, assorted spices] and provided on the side cooked TVP chunks, cooked slices of keilbasa, cooked boneless skinless chicken, cooked diced ham, sauteed cubanelle peppers to be added in for protein. I also made bread, ‘antipasta’ of frozen broccoli and cauliflower florettes, sliced red onion, black olives, marinated artichoke hearts and rinsed canned butterbeans in a zesty italian dressing, had a fairly generic tossed salad of iceberg and romaine with baby spinach and that multipack of salad dressing from BJ’s Wholesale Club [zesty italian, ranch and can’t remember offhand what the third one was, french maybe?] I pucked up a bunch of fruit for dessert - apples, grapes, bananas and oranges.
Oddly enough, hauling everything to Pennsic was more work than getting it on the table - as long as I had a firepit to cook the soup on, everything else was all premade. Reheating the proteins went fairly quickly as they were all precooked and sealed in boil in bag sealer bags and got dumped into a pot of hot water to reheat, then poured out into their bowls.