Preheat oven to 380 degrees F (180°C). Line a baking sheet with parchment paper.
Using an electric mixer, beat eggs and sugar until the mixture becomes thick, fluffy, and triples in volume.
Using a spatula, gently fold in flour and cocoa powder.
Spread the batter evenly in thin layer into the prepared baking sheet. Bake for 7 to 8 minutes in the preheated oven until a toothpick inserted in center of biscuit comes out clean.
Turn upside down onto clean kitchen towel and carefully remove parchment paper. Let cool down.