Preheat oven to 350 degrees. Line an 8 x 8 inch cake pan with parchment paper. Allow the paper to hang over the sides to use as handles to lift the cake out
In a large mixer bowl whisk or sift the coconut flour, baking powder, salt, sweetener, and cocoa powder until fully combined and no lumps are in the dry ingredients
Add the eggs, Beat on low about 10 seconds to moisten the dry ingredients, Increase speed to medium-low, Beat on medium-low about 30 seconds or until fully combined
Scrape down the sides of the bowl. Add the butter. Beat on low about 10 seconds to break up the butter. Increase the speed to medium. Beat on medium about 30 seconds or until fully combined and smooth
Scrape down the sides of the bowl. Add 1/4 cup of the milk. Add vanilla extract. Beat on low about 10 seconds or until the milk begins to combine. Increase the speed to medium. Beat on medium until fully combined and smooth
Scrape down the sides of the bowl. Add the remaining 1/4 cup milk. Beat on medium another 30 seconds or until fully combined and the batter is light and creamy
Scrape down the sides of the bowl once again and push all the batter to the center of the bowl. Scoop the batter into the prepared cake pan. Use a spatula and spread the batter evenly throughout the cake pan.
Bake at 350 degrees for 25-30 minutes or until a tester comes out clean.
Remove the cake from the oven. The cake will be soft but will firm up as it cools. Allow the cake to cool in the pan 1 hour or until firm enough to transfer
Grasp the over hanging parchment paper. Transfer the cake to a wire rack. Allow to cool completely before frosting.