Place the butter, water, and chocolate in a 12-oz. mug and microwave for about 30 seconds, or until melted.
Carefully stir the erythritol and vanilla extract into the chocolate mixture.
Add the egg to the mug, and beat well until everything is fully combined and glossy.
Whisk in sour cream.
Mix in the Chocolate Keto Chow and almond flour.
Microwave on full power for about 60-90 seconds,* or until the cake is risen and begins to pull away from the sides.
While the cake cools, make the frosting. Mix the melted butter, powdered erythritol, and Salted Caramel Keto Chow together in a small dish.
Stir in the coconut and pecans.
When the cake is cool, cut it in half horizontally to make two layers.
Spread half the frosting on the bottom half of the cake. Place the second layer over it and cover the top with the remaining frosting.