In a bowl, add eggs, sugar, oil, orange juice, and orange zest. Mix with a whisk for one to two minutes. Then add the flour, baking powder, and a pinch of salt. Mix again until you have a smooth batter. Line a square baking pan with parchment paper, pour most of the batter in, and leave a small amount in the bowl. Add the two teaspoons of cocoa powder to the remaining batter and mix.

Drop spoonfuls of the cocoa mixture onto the cake and use a fork or knife to create various designs. Bake in a preheated oven at 350°F (180°C) for 30 to 35 minutes. (Every oven is different, so use the knife trick to check the cake's texture! If it needs more baking, adjust accordingly!)