Preheat the oven to 180C/350F. Line an 8-inch cake pan with parchment paper and set aside.
In a mixing bowl, add your coconut flour, salt, and baking soda and set aside.
In a separate bowl, add your egg whites and cream of tartar and beat together, until still peaks form and set aside. In another mixing bowl, add your coconut oil, sweetener, and egg yolks and whisk together, until combined and glossy.
Add the dry ingredients into the sweetener and oil mixture, until combined. Gently fold through your egg whites until completely combined. Transfer the cake batter into the lined cake pan.
Bake the cake for 20-25 minutes, or until a skewer comes out clean. Remove from the oven and allow the cake to cool completely, before frosting.
To make your frosting, prepare the vanilla frosting as directed, but add the coconut extract and shredded coconut flakes. Add extra water or milk, until desired thickness. Frost the cake.
TO STORE: Leftover cake should always be stored in the refrigerator, covered, to keep it moist. As it is a keto cake, I recommend you consume it within a week. Any longer and the cake will become quite soggy. TO FREEZE: Place leftover slices of cake in a shallow container and store in the freezer for up to 2 months. Thaw overnight in the refrigerator.