Place the almond flour, coconut flour, cacao powder, beetroot powder, baking soda, Erythritol and vanilla powder in a bowl and combine well.
Add the eggs, melted coconut oil and sour cream and mix until well combined.
Divide the mixture between two mugs.
Microwave each mug cake on high for 70-90 seconds.
Meanwhile, prepare the frosting by mixing the butter, remaining Erythritol, cream cheese and vanilla.
For a smooth texture, use a blender.
Instead of the frosting, you can use whipped cream or creamed coconut milk with a dash of vanilla.
Preheat the oven to 175 °C/ 350 °F and cook for about 12-15 minutes or until cooked in the centre.
Let the mug cakes cool down.
Place the frosting in a piping bag or simply spoon it on top of each mug cake.
Enjoy!