Preheat oven to 140C (fan)

Roughly tear some baking paper to fill a 7-8 inch square tin. Stick down to the tin with some butter if you like. No need to grease the paper if using baking paper.

Melt together the butter and chocolate in a bowl over simmering water

Whisk together the eggs and sugar. No need to go crazy as long as all is well combined

When the chocolate and butter is all melted remove from the heat and grate in some 100% cacao to add richness. Alternatively add up to 50g cocoa powder

Add the chocolate mixture to the egg yolks and fully combine

Gently fold in the flour with a metal spoon.

Pour into the tin and bake for 50-55 mins until the top is not wobbly when shaken and the brownies are not noisy when you listen to them

Remove from oven and place tin into a sink filled with 1 inch of cold water. This stops the edges drying out.