This is a success with my family. I find it turns out best if I don't measure anything.
Preheat oven to 375.
Add to bowl:
2 lbs of lean ground beef
1/2 cup gluten free oats
1/4 cup of organic ketchup or tomato paste
1/4 cup of almond milk
Let the oats absorb the milk/tomato, about 10 minutes. Mix with your hands.
1 onion, diced
a splash of wheat-free tamari
1 can of sliced mushrooms
Bake in oven for about 1 hr. Serve with oven fries and veggies.