2 tsp cocoa
1 tbsp milk
1/4 tsp b.powder
Heat oil slightly, add the cocoa, milk and stir. Leave it aside to cool.
Whisk egg and sugar till light and fluffy. Add in the flour and b.powder. Pour little of the egg mixture into the oil mixture to lighten the flour. Pour the mixture back into the egg and fold in lightly.
Grease a 10 x 13 in jelly roll pan and preheat the oven to 375 degrees. Pour into the pan and bake for 10 minutes. Take out and let cool, invert onto a greaseproof paper. Cool down. Apply fillings and roll. Keep in the fridge to firm up.