Orange is peeled and cleaned well from the skins. Grind in a food processor. Add the egg and melted butter again and crashed. Yogurt mix with baking soda and flour mixed with baking powder, salt and sugar. Both mixtures were added to the main and break more. Finally, put the chocolate. Fill forms for muffins to 2/3 of their capacity. Cupcakes bake in a preheated oven 200C degrees, 15-20 minutes.