Preheat the oven to 180°C.
Combine chicken breast, oatmeal, protein powder, cocoa powder, and baking powder in a bowl and mix well.
Add egg, unsweetened milk, and erythritol. Mix thoroughly to make the batter.
Pour the batter into a mold and flatten it evenly.
Bake in the preheated oven for 20–25 minutes.
Let it cool before serving.