No Thought Needed Shepard's Pie

Most of what I make regularly is really flexible. Feel free to mix it up and do whatever. For the beef, we buy a big thing of ground beef and cook it up all at once. Then we separate it into ziplock bags that represent about a pound and freeze them. A lot of my meals use these as a foundation.

1lb browned ground beef (I just grab a bag from the freezer and nuke it for 2 min)
14 oz can of diced tomatoes
6 oz can of tomato paste
14 oz can of green beans drained
couple of cups of frozen corn
cheese (or not. depends on how healthy I'm making it)
a few cups of mashed potatoes
salt and pepper to taste

Layer the ingredients pretty much in that order in a large pie dish or a square baking dish. I bake at 350F for about 20 min. Serve and eat.