Preheat the oven to 180C.

Cream the peanut butter and sugar together in a bowl (or a food processor if you're lazy like me!)

Mix in the egg until totally combined.

Add the ginger and the flour and mix well, it will be a very stiff, crumbly mixture. If using a food processor, add all the ingredients to the processor and and mix for a few seconds until you have a firm dough.

Grease a 15x20cm rectangle tin.

Press the dough into the tin and flatten using your hands or the back of a fork.

Cook for 15-20 minutes until golden brown.

Leave to cool in the tin.

When cool, melt the milk chocolate on low in the microwave or in a bowl over a pan of hot water.

In a separate bowl, repeat with the white chocolate.

Spread the milk chocolate over the traybake, then drizzle the white chocolate on top.

Allow to set and then cut into pieces using a sharp knife and remove from the tin.