Sautee the onion or leek until tender
Add in the ground beef and cook until most pink is gone
Add in spinach and cook until tender, set aside mixture and add salt and pepper
Mix together in a separate bowl the egg, cauliflower, cheese and almond flour. Add a bit of salt and pepper
In a greased whoopie pie pan, add about 2 tablespoons of mixture and press in the middle to make a slight ridge around the circumference. If you don't have a whoopie pie pan, flatten balls of the mixture onto a greased baking sheet and press the middle and make ridges around the outer area. Do not use a muffin tin - I tried this and they were difficult to remove without breaking apart.
Spoon about a tablespoon of mixture onto the crust
Bake 15-20 minutes, until crust is golden