Preheat oven to 400˚Grease a ramekin with butter.
In a small bowl, beat the egg, and add the coconut flour, almond flour, baking powder, salt, almond milk, and butter. Stir to combine.
Add the spinach, garlic powder, and feta, and stir until evenly distributed.
Spoon the mixture into the ramekin, and bake for 10 to 15 minutes.
Allow them to cool for 5 minutes, then invert the ramekin, and take the bread out.