Heat oven to 180°C, line a brownie tin with baking parchment
Zest one of the Jaffa Oranges
Place the butter, dark chocolate and orange zest in a non-stick saucepan and very gently melt over a low heat, stirring every now and then, until smooth – take care not to overheat it. Leave to cool
Whisk the eggs and sugar together until the mixture is pale, has doubled in volume and leaves a trail when the whisk is lifted
Gently stir into the cooled chocolate mixture. Sift over the flour and cocoa, stir in, then add the chopped chocolate orange
Slice the top off each Jaffa orange and scoop the inside out. Save the fruit to eat later. Spoon the brownie mixture into each Jaffa orange and place the top of the Jaffa orange back on top of the mixture
Wrap tightly with foil and place in the oven, bake until the brownie is cooked through, roughly 35 minutes
