Preheat the oven to 180°C (356°F).
Mix protein powder, almond flour, and baking powder in a bowl.
Add eggs, unsweetened yogurt, and erythritol. Mix well.
Pour the batter into a pound cake mold.
Bake in the oven at 180°C (356°F) for 25-30 minutes.
Let it cool and slice into servings.