• 250 g butter
• 250 g dark chocolate (at least 70 per cent cocoa solids), broken into pieces
• 4 free-range eggs
• 400 g golden caster sugar
• 125 g plain flour
• 90 g cocoa powder
• 125 g milk or dark chocolate, roughly chopped, or white chocolate chips

Preheat the oven to 200°C/fan 180°C/gas mark 6. Line a 23cm square baking tin with nonstick baking paper, or use a 23cm silicone tray.

Place the butter and dark chocolate in a heatproof bowl set over a saucepan of simmering water over a low heat and stir until just smooth. Allow to cool.

Place the eggs and the sugar in a bowl and beat until light and creamy. Using a spatula or a large metal spoon, fold in the chocolate mixture. Sift over the flour and cocoa powder and mix to combine. Add the chocolate chunks or chips, then pour the mixture into the prepared tin or tray.

Bake for 35–40 minutes, until just set in the middle. You cannot use a skewer to test brownies for readiness as they will always be moist. They will firm up after cooling, so always err on the side of cooking them less. When cool, cut into 20 bite-sized pieces.