Ingredients
185g unsalted butter
185g best dark chocolate
85g plain flour
40g cocoa powder
50g white chocolate
50g milk chocolate
3 large eggs
275g golden caster sugar

Method
STEP 1
Cut 185g unsalted butter into small cubes and tip into a medium bowl. Break 185g dark chocolate into small pieces and drop into the bowl.

STEP 2
Fill a small saucepan about a quarter full with hot water, then sit the bowl on top so it rests on the rim of the pan, not touching the water. Put over a low heat until the butter and chocolate have melted, stirring occasionally to mix them.

STEP 3
Remove the bowl from the pan. Alternatively, cover the bowl loosely with cling film and put in the microwave for 2 minutes on High. Leave the melted mixture to cool to room temperature.

STEP 4
While you wait for the chocolate to cool, position a shelf in the middle of your oven and turn the oven on to 180C/160C fan/gas 4.

STEP 5
Using a shallow 20cm square tin, cut out a square of non-stick baking parchment to line the base. Tip 85g plain flour and 40g cocoa powder into a sieve held over a medium bowl. Tap and shake the sieve so they run through together and you get rid of any lumps.

STEP 6
Chop 50g white chocolate and 50g milk chocolate into chunks on a board.

STEP 7
Gently fold in this powder using the same figure of eight action as before. The mixture will look dry and dusty at first, and a bit unpromising, but if you keep going very gently and patiently, it will end up looking gungy and fudgy. Stop just before you feel you should, as you don’t wan