Preheat the oven to 180°C (356°F).
Melt the dark chocolate using a double boiler.
Cream the butter and erythritol together in a bowl.
Add the egg and mix well.
Sift in almond flour, cocoa powder, and baking powder, then combine.
Add the melted dark chocolate and mix into a dough.
Scoop portions of the dough onto a baking tray lined with parchment paper.
Bake at 180°C (356°F) for 12-15 minutes.
Let cool before eating.