This simple recipe requires only 3 ingredients: sliced pork loin (already mentioned minute steaks or easy steaks), shallots and teriyaki sauce. It's also one of the lazy recipes — part of it you can prepare evening before, and finish it quickly before serving or packing your bento box. Plus, marinating for a long time allows increased flavors to transfer easily across the meat!
Tamagoyaki is a great and easy to make bento ingredient. It's savory taste goes well with vegetables and diary ingredients, it packs a reasonable amount of protein and will satisfy your hunger for a long time. It's good served warm, as well as cold.
You can buy thin beaf slices in some grocery shops or butchers. They may be called minute steaks or quick steaks and are a great ingredient that you can use to make a quick donburi (a rice bowl with meat and vegetable toppings). It's so fast to prepare, that you can do everything in the time it takes to cook the rice!