Mix almond flour and cocoa powder in a bowl.
Add erythritol, baking powder, and salt, and mix well.
Add eggs, unsweetened almond milk, and vanilla extract to make the batter.
Fill the donut mold with the batter.
Bake in a preheated oven at 170°C for 15 minutes.
After cooling, melt unsweetened dark chocolate in a double boiler and coat the donuts.