Mix the egg with the sugar. Soda is added to the yoghurt and effervescent when added to the mixture, and then the chocolate and the oil and stir again good. Gradually add flour and stir a few minutes until the mixture is homogeneous. Grease the tin with sunflower oil and sprinkle with flour and pour it into the mixture. Bake in a preheated 180C oven for about 20 minutes. Should be peeled from the tray. When checking with a toothpick in it there should be no mixture (must be dry). Once the cake out of the oven is cut and allowed to cool. The products of the covering medium is placed in a small saucepan and medium strong cooker confused, until melted sugar. With warm mixture watered cake as partitions Leave for an hour or two to take topping. * The tray has dimensions 36h27 cm.