- STEP 1
Lightly grease and line a 900g loaf tin. Pre-heat the oven to 160 c/325 f/ Gas Mark 3. Put the margarine, sugar,flour, baking powder, eggs, milk and vanilla extract into a large bowl and beat together for about 2minutes, until well blended. Spoon half the mixture into another bowl and set aside.
- STEP 2
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.
- STEP 3
Spoon the vanilla and chocolate cake mixtures randomly into the prepared tin until all of the mixture is used up and gently level the surface. Bake for 50 minutes - 1 hour, until the cake is well risen, springy to the touch and beginning to shrink away from the sides of the tin. Allow to cool in the tin for a few minutes, then turn out onto a wire rack, remove any lining paper and leave to cool completely.
- STEP 4
For the icing, melt the margarine in a small pan, add the cocoa powder, stir to blend and cook gently for 1 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.
- STEP 5
Spread the cake evenly with the icing, then drizzle the melted white chocolate over the top. Leave to set.