Chocolate swiss roll

I baked a chocolate Swiss roll today but I have a lot of batter left so I baked a 7" round cake with it.

Here is the recipe I use:

20g chocolate emulco and 30g cocoa powder mixed with 70g hot water

4 egg yolk, 50g sugar and 1g salt beat together then add 50g cooking oil and 60g milk

120g superfine flour, 2g baking powder, 2g sodium bicarbonate added to the egg yolk mixture

4 egg whites, 60g castor sugar and 1g cream of tartar, beat until stiff then add to the above mixture.

Bake in preheated oven at 180C for 15mins for swiss roll

Bake in preheated oven at 180C for 30mins for cake

I like the cake, it is moist. I use the peanut butter butter-cream on the cake, it is yummy.