Cut parchment paper to fit bottom of a greased 9-inch round cake pan or use a silicone non-stick pan.
In large mixing bowl, combine the almond flour, coconut flour, sweetener, baking powder, xanthan gum and salt.
Add the almond milk, coconut oil, butter, and vanilla to the dry mix and beat with an electric mixer on medium-high speed for about 2 minutes, scraping bowl as needed.
Add the eggs and continue to beat an additional 2 minutes.
Spread batter into prepared cake pan.
Bake in 350 °F oven for about 25-30 minutes or until toothpick inserted in center comes out clean and cake springs back when lightly touched.
Cool cake for 10 minute then transfer to wire rack to cool completely.
For frosting: Microwave chocolate and butter in microwaveable bowl on HIGH for 1 minute or until butter is melted. Stir until chocolate is completely melted and incorporated into butter. Add sugar and enough almond milk to reach desired consistency.
Spread frosting evenly over the top of the cake.
Notes
To reduce total carbs, sweetener in cake could be reduced to ½ cup and omit frostingMakes 12 slicesPer slice:165 calories, 15.7g fat, 4.5g carb, 2.3g fiber, 2.2g NET carbs, 3.6g protein, 35g erythritol