Impossible Gluten Free Cheeseburger Pie

This version of Impossible pie went over really well tonight. I have a large family and made one of this kind and one of the Taco.

1 lb ground beef
1 onion, diced
salt and pepper
1 cup milk
4 eggs
1/4 cup corn flour (not corn starch. It's yellow corn flour)
1/4 cup fine white cornmeal (or rice flour)
1/4 cup potato starch
1 can green beans (10 oz)
2 tomatoes, sliced
1 generous cup shredded cheddar or mozzarella cheese

Heat oven to 400 F
Brown ground beef and onion in frying pan. Stir in salt, pepper and and green beans.
Put in a lightly greased 10" deep pie plate
Beat milk, eggs and flours together, until smooth
Pour over meat mixture.
Bake for 25 minutes.
Arrange fresh tomato slices on top of meat. Sprinkle on cheese. Return to oven and bake an additional 5 - 8 minutes until cheese is melted.
Let cool for a couple of minutes. Slice and serve.
Serves 6
We also thought that fresh mushrooms sauted in butter would be good in place of the green beans.