Cook beef and onion in skillet until meat is brown, about 8-10 minutes.
Spread beef mix into pie plate and sprinkle in salt.
Mix together coconut flour, almond flour, baking powder, almond milk and eggs.
Pour the egg mixture evenly over the meat. Sprinkle about 1 cup of cheese on top.
Bake at 400°F for about 25 minutes.
Remove from oven and top with optional tomato if desired and remaining cheese. See recipe notes for other possible toppings.
Bake an additional 5 minutes.
All almond flour can be used if you don't care for coconut flour. You can also use a baking mix like Carbquik if desired.In addition to tomatoes, the following can top off the pie before the final baking: