My mom used to make and freeze sandwiches for us to pop into the toaster oven any time we wanted one. Twenty four sandwiches sounds like a lot, but they go quickly!
You will need meat and cheese and buns.
I used:
1 lb orange chipotle Turkey
20 sliced assorted cheeses
24 small hamburger buns
Lay them out for easier assembly.
Saute some onion (I used one large sweet onion, finely chopped) in oil, season while it cooks. Once the onion is translucent add 1 stick butter, 2 Tbsp. Mustard or other condiment, and fresh herbs. I used Dijon mustard and Italian seasoning.

Then tear off 24 pieces of foil and lay out the buns for assembly.
Top each bun with the cooked onion spread.
Top with meat and cheese.

Wrap in foil and freeze.
To prepare, Bake at 350 in toaster oven 15 minutes. Cheese will melt and bun gets crispy.
The original version had a little Worcestershire sauce and poppy seeds in the sandwich spread. Needless to say the variations are endless!