This is a doria (rice au gratin) made with my family's standard chicken rice and white sauce. I've been making this for years.
You can make lots of chicken rice and keep it in the freezer. It's good to pack in your bento as well.

Bake in the oven if you are making a big batch (12-13 minutes at 220°C). The baking time will depend on your oven, so keep an eye on it and adjust accordingly. It's convenient to make a lot of white sauce and keep it in the freezer.. Recipe by Yuuyuu0221