Instructions

Pre-heat the oven to 330°F/170°C.

Dice butter into small cubes and tip into a bowl. Break the block of dark chocolate into small pieces and drop into the bowl.

In a double boiler, gently heat the butter and chocolate until melted, stirring occasionally.

Remove the bowl from the pan and leave to cool.

Butter and flour a 8" square tin, and line with baking parchment.

Whisk the eggs and sugar until pale and creamy and until a spoon leaves a mark for at least 2 seconds. Add the cooled chocolate and fold together gently, preserving the air but folding until well blended.

On top, sift the cocoa, salt and flour mixture.

Gently fold it all together, being careful not to over-handle.

Finally, shake the chocolate chips on top, letting them sink in.

Pour the mixture into the prepared tin.

Put in the oven for 25 mins. It should be just ever-so-slightly wobbly. Bake for a few more minutes if necessary.

Leave the whole thing in the tin until completely cold, then cut to serve.