Fudgy brownies

Preheat the oven to 180ºC (350ºF, gas mark 4). Grease an 18 cm (7 in) square shallow cake tin and line the bottom with baking parchment.

Break up the chocolate and put it in a heatproof bowl with the butter. Set the bowl over a pan of simmering water, making sure the water is not touching the base of the bowl. Leave until melted, then remove the bowl from the heat and set aside to cool.

Stir the caster and muscovado sugars into the chocolate mixture together with the vanilla extract. Gradually beat in the eggs and yolk. Sift over the flour and cocoa powder, and stir until evenly blended. Do not overmix.

Pour the mixture into the prepared tin. Bake for about 30 minutes or until risen but still slightly soft in the middle – a skewer inserted in the centre should come out with a few moist crumbs sticking to it. The surface will look cracked. It is important not to overcook or the brownies will be dry.

Leave in the tin for 5 minutes, then turn out onto a wire rack and leave to cool. When cold, peel off the lining paper and cut into 16 squares. If possible, wrap the brownies in foil and leave until the next day before eating. They can be kept like this for 3–4 days.