Pre-heat the oven to 175°C (350ºF) and prepare a cake tin (I used a deep, rectanglur one, slightly larger than 8″ x 8″).
Melt all of the 200g (7oz) white chocolate (see note 2) and then set to one side until completely cooled.
Using a mixer or electric whisk, mix the sugar and butter until light and fluffy.
Add in the eggs one at a time followed by half of the melted chocolate (keep the rest for the frosting).
In a separate bowl, mix the dry ingredients together. Then, alternating the dry ingredients with the milk, add to the wet ingredients until the batter is nice and smooth.
Bake for around 40-45 minutes until an inserted skewer or toothpick comes out clean. You may need to cover the top of the cake with baking paper if you find it is browning too quickly.
Leave to cool in the pan for around ten minutes and then turn out on to a wire rack and allow to cool completely before frosting.