One Bento, Side dish, and Snack recipe with Champignons

Cheese and mushroom casserole with chicken

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! :-)