Melt dark chocolate and butter in Bain Marie and cool
2 Grease and line a square tin
3 Whisk eggs and sugar for 5 mins
4 Add cooled chocolate mix to eggs and gently fold
5 Add Sieve flour and Cocoa to eggs and gently fold
6 Pour into tin
7 Bake in preheated oven for 25 mins then continue until it doesn't wobble