Preheat the oven to 180°C.
In a bowl, mix together protein powder, almond flour, cocoa powder, and baking powder.
In another bowl, combine eggs, unsweetened almond milk, olive oil, and erythritol, then mix well.
Pour the liquid ingredients into the dry mixture and mix thoroughly.
Pour the batter into a brownie pan.
Bake at 180°C for 18-20 minutes.
Let it cool before serving.