What you'll need:
200g dark chocolate
275g light soft brown sugar
1tsp vanilla extract
Preheat the oven to 180c. Grease and line a baking tin with baking paper.
In a pan, heat the butter and and chocolate and continually stir until they have melted together and are nice and glossy.
Take the pan off the heat and and mix in the sugar, then eggs and vanilla (tasting as you go of course).
Sift the flour into the pan and stir gently.
Pour into your tin and place in the middle of the oven. Bake for 15-20 minutes until the top is nice and crusty.
Leave to cool for 5-10 minutes (if you can bare to) then cut into 12 squares.
Stack them up, dust with icing sugar and go wild with your toppings.