200 g (7 oz) plain dark chocolate, broken into pieces
125 g (4 oz) unsalted butter, softened
275 g (9 oz) light muscovado sugar
4 eggs, beaten
1 teaspoon vanilla extract
50 g (2 oz) ground almonds
50 g (2 oz) cocoa powder
Line a shallow 23 cm (9 inch) square cake tin with baking paper.
Heat the chocolate and butter in a heatproof bowl over a pan of simmering water, making sure the base of the bowl doesn't touch the water, until melted and smooth. Remove from the heat and cool slightly.
Add the sugar and beat together. Gradually beat in the eggs and vanilla extract to the melted chocolate mixture. Add the ground almonds, sift in the cocoa powder and stir well to mix.
Spoon the mixture into the prepared tin and bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 20 minutes until just firm to the touch but still a bit soft. Leave to cool slightly before cutting into 16 squares.