Combine oatmeal and almond flour in a bowl.
Add protein powder, unsweetened cocoa powder, and baking powder.
Mix in erythritol, salt, vanilla extract, and unsweetened almond milk.
Break unsweetened dark chocolate into small pieces and add to the dough.
Shape the dough into thick, round cookies.
Bake in a preheated oven at 180°C for 13-15 minutes.