Beef Shigureni Bento

Beef shigureni is thinly sliced beef cooked in a sweet and salty sauce with ginger. This strongly flavored beef lasts for up to a week in the refrigerator, establishing it as a great make-ahead dish for bento. Any cut of beef will work, such as tri-tip, or you may prefer meat with a little fat. Thinly slicing raw beef by hand can be difficult, so partially freeze it first; the firmer beef will be much easier to slice.