Mix Dry Ingredients: Combine semolina and sugar in a mixing bowl.
Add Yogurt and Oil: Add yogurt and vegetable oil to the mixture, using the same cup for measurement to ensure consistency.
Rest the Mixture: Mix well until homogeneous, then cover and let rest for 15 minutes.
Add Baking Powder and Flour: Mix in baking powder and flour until well combined.
Prepare Cocoa and Flour Mixtures: Divide the batter into two bowls. In the first bowl, add raw cocoa; in the second bowl, add an additional two tablespoons of flour.
Grease Tray: Grease a baking tray with butter.
Layer the Mixtures: Alternate spoonfuls of the cocoa and flour mixtures into the tray.
Create Marble Effect: Use a wooden stick to swirl and create a marbled effect.
Bake: Bake in a preheated oven at 180°C (356°F), checking for doneness with a skewer.
Cool and Serve: Allow to cool before serving. Can be enjoyed hot or cold.