In a small mixing bowl, add the almond flour, coconut flour, brown sugar, baking powder, ginger, allspice, cinnamon, egg, and milk and mix well. If the batter is too thick, add extra milk.
Grease a microwave safe mug or bowl generously and pour the batter in it and microwave for 1 minute. If the cake is undercook, microwave in 20 second bursts until done. Remove from the microwave and let sit for one minute.
Oven option
Follow as above, but bake in an oven safe dish at 180C/350F for 10 minutes.