This casserole is simple and delicious, and makes a perfect snack during a picnic (bento anyone?)—you should use it as a basic idea for a casserole, since the pasta sauce is the stable and the most important piece of the meal. It's also a very tweak-able recipe! :-)
I didn't plan to make this cake at all, what I did plan was apple tart with apricot jelly... Well, sometimes I just change my mind, especially while experimenting in the kitchen :-) The result is interesting, refreshing and citrusy! :-) If you don't like the strong orange aroma, you can replace them with any soft and sweet fruit: peaches, pears, and apricots should do fine!
Tuna paste is ridiculously easy to prepare and makes a great no cooking bento, cutting the preparation time to less than 20 minutes, including rice cooking time! Now, that's what I would call cooking on the go! You can also use the tuna paste for a great tasting onigiri or sushi.