Having made my legendary brownies countless times, thought would give these a try
Ingredients
7oz butter
7oz dark chocolate
Zest of an orange
12oz caster sugar
4oz plain flour
4 eggs
2oz cocoa
4oz dark chocolate orange chopped

Method
Heat oven to 180/160fan/gas 4
Line a 20×24 tin with baking parchment

Put butter, chocolate and grated zest into a non stick pan and gently melt, leave to cool.
Whisk eggs and sugar with electric whisk until mixture is pale, doubled in volume and leaves a trail when beaters are lifted.
Gently stir in chocolate mixture. Sift over flour and cocoa, stir in, then add chopped chocolate orange.
Poured into lined tin and bake for 35-40 mins.