Preheat the oven to 180C/350F. Grease 3, 8-inch springform cake pans and set aside.
In a mixing bowl, add your coconut flour, arrowroot flour, baking powder, baking soda, and salt, and mix until combined. In a separate bowl, combine your coconut oil, maple syrup, and cocoa powder and whisk together until glossy. Add the eggs in, one at a time, until combined. Add the milk and vanilla extract and whisk together, until combined.
Gently fold through the dry ingredients and mix until thick and dense. Distribute the batter evenly amongst the three cake pans. Bake the cakes for 27-30 minutes, or until a skewer comes out mostly clean.
Remove the cakes from the oven and let them cool completely. Once cool, layer the cake. Place the first cake on a flat surface. Spread it with frosting before adding the second cake on top. Spread with more frosting, before adding the final layer. Spread the top with the remaining frosting, along with the exterior of it. Let the cake sit for 20 minutes, before serving.
* For a keto coconut flour cake, use keto maple syrup. TO STORE: To ensure the cake remains moist, store it in the refrigerator, covered, for up to 1 week.TO FREEZE: Place slices of the cake in a shallow container and store them in the freezer for up to 6 months.