In the bottom of a good strong blender (I recommend Blendtec or Vitamix), add eggs, almond milk or water and vanilla extract. Blend briefly to combine.
Add almond flour, coconut flour, cocoa powder, sweetener, baking powder and salt. Blend on medium high until smooth (you may need to scrape down sides of blender a little to make sure everything combines). Add melted coconut oil and blend until combined.
This updated recipe uses a liquid oil, like avocado oil, in place of the melted coconut oil. The coconut oil is delicious but it thickens the batter considerably, making it harder to get out of the blender.