Preheat the oven to 160°C/325°F/gas mark Lightly grease two 7inch shallow cake tin. Line the bottom with a circle of non-stick baking parchment.
Measure the butter, sugar, flour, baking powder, eggs, milk and vanilla extract into a large bowl and beat with a hand-held electric mixer for about two minutes, until well blended. Spoon half into another bowl and set aside.
In a small bowl, mix the cocoa powder and hot water together until smooth. Allow to cool slightly, then add to one of the bowls of cake mixture, mixing well until evenly blended.
Spoon the chocolate mixture evenly into the two pans, if you have four tins the same size you can do the vanilla at the same time or wait until the chocolate has baked and wash the tins and repeat. Bake for 15-20 minutes, until the cake is well risen, springy to the touch and starting to shrink away from the sides of the tin. Allow to cool in the tin for a few minutes, then turn out on to a wire rack, peel off the lining paper and leave to cool completely.
To make the icing, melt the butter in a small pan, add the cocoa powder, stir to blend and cook gently for one minute. Stir in the milk and icing sugar, then remove from the heat and mix thoroughly. If necessary, leave the icing on one side, stirring occasionally, to thicken. Spread the cold cake evenly with the icing.
To make the chess board using 2 round cutters one medium and one small. Cut the same large circle into all the pieces and then cut the smaller circles.
When you have all the pieces – 3 per cake so 12 all together – interchange the pieces so the outer ring would be white and then the middle would be chocolate and the middle white again and vice versa with the chocolate large outside ring. Pile up the layers so they are in contrast with each other.If you want you can put a thin layer of icing between each layer to level the cake and stick the layers together but it isn’t too important. As long as the outside is iced the layers wouldn’t move too much.