I have to keep ready made lunches around so hb can just grab.
Lately, he's been into chicken sandwiches.
Tyson makes these precooked breaded patties, and I use packaged hamburger buns.

I'll make 3 or so ahead of time by just putting the patty and bun in a zip bag. He takes the patty out and micros it for about 40 secs, then spreads mayo on. Easy and very tasty.