As I posted yesterday, making individual pies in muffin or cupcake liners is a great way to make 'planned leftovers' from dinner look neat enough to put into a bento box. As Sile suggested in the comments, if you don't want to use throwaway paper cups, silicone cups are a reusable alternative. Calphalon makes a nice silicone liner and cupcake pan set which would be perfect for this. The liners are in pretty pastel colors.
![calpha_cupcake.jpg](http://justbento.com/files/bento/images/calpha_cupcake.jpg)
You can also use the liners as dividers in your bento, for salads, fruit, and so on. They sell the tin and liners as a set, as shown here, or the liners on their own. Extras might be a good idea to have if you do freeze the food 'cupcakes'.