Heat the oven to 190C/170C Fan/Gas 5. Line a 20x30cm/8x12in baking tin with baking paper.
Gently melt the butter and the sugar together in a large pan. Once melted, take off the heat and add the chocolate. Stir until melted.
Beat in the eggs, then stir in the flour and the cocoa powder.
Pour the brownie batter into the prepared tin and bake for 30–35 minutes, or until the top of the brownie is just firm but there is still a gentle wobble in the middle.
Take out of the oven and leave to cool in the tin. Cut the brownies into 5cm/2in squares when only just warm, or completely cool.
Recipe Tips
The secret to making the best, fudgy, squidgy brownie is not to overbake them. They should wobble in the center when you take them out. The residual heat will continue to cook them for a few minutes and they’ll set up on cooling. Too firm and they will be more cakey than fudgy.
You can easily make these brownies gluten-free by swapping in gluten-free flour. If you’d like to jazz them up with nuts, chocolate chips, or both, add these after the addition of the eggs, when the batter is somewhat cooler and will not melt the chocolate straight away.