Preheat oven to 350 degrees. Line an 8 inch round cake pan with parchment paper.
In a large mixer bowl whisk together coconut flour, baking powder, salt, and monkfruit sweetener until fully combined and no lumps are in the flour
Add the eggs and beat on low for 10 seconds or just until the dry ingredients are moist. Increase speed to medium and beat on medium for about 30 seconds or until fully combined.
Scrape down the sides of the bowl if needed. Add the butter and beat on medium for another 30 seconds or until combined and smooth
Scrape down the sides of the bowl again if needed. Add vanilla extract and 1/4 cup of the milk. Beat on medium about 30 more seconds or until fully combined
Use a hand whisk and test the dough. If the whisk moves through the batter easily and the batter feels creamy and light it is ready to be baked. If it is still thick and the whisk does not move easily through the batter then add the remaining 1/4 cup of milk (I used the entire total of 1/2 cup of milk)
Scrape down the sides of the bowl if needed. Beat on medium for another 30 seconds after adding the remaining milk (if using). Scrape down the sides of the bowl and push the batter to the center of the bowl. Use a hand whisk and whisk the batter a few times to make sure it is light and creamy.
Pour batter into the prepared cake pan and use a spatula to spread the batter evenly throughout the pan. Bake at 350 degrees for 30-35 minutes or until golden on the edges and a tester comes out clean (mine took about 33 minutes) The cake will still be a little soft but it will firm up as it cools
Cool in the pan for at least 45 minutes to 1 hour so all the ingredients can set into place
After it has cooled use a butter knife and CAREFULLY loosen the edges of the cake from the sides of the pan. GENTLY turn the cake onto a wire rack. Be very careful the cake will still be warm and fragile. Allow to cool completely before frosting or cutting.