Dark chocolate, roughly chopped or broken 200g
Unsalted butter 175g
Caster sugar 325g
Plain Flour 130g
Preheat the oven to 170°C (325°F) Gas Mark 5.
Put the chocolate and butter in a heatproof bowl over a saucepan of simmering water (do not let the base of the bowl touch the water) Leave until melted and smooth, stir occasionally. Remove from the heat once the chocolate has melted and add the sugar, stirring well into the mixture. (I usually use a large wooden or metal spoon.) Add the flour and stir until well incorporated. Finally, stir in the eggs and mix until thick and smooth.
Spoon the mixture into a greased baking tray or silicone mould. Bake for 30-35mins, or until flaky on top but still soft in the centre. (Be careful not to overcook otherwise the edges will become hard and crunchy.)
Leave to cool completely before cutting and serving.