Preheat the oven to 200'C.
Melt the chocolate and the butter in a heatproof bowl over simmering water.
Whisk the whole eggs, egg yolks, sugar and zest of the orange until the mix has doubled in volume.
Add the flour and then the melted chocolate and butter. Spoon the mixture into individual pudding moulds, or lined stainless steel rings and cook for 10 minutes. Serve straight from the oven. They should still be runny in the middle.
Boil the orange juice with the sugar for 10 minutes until the mixture has reduced and is a syrupy consistency.
«The batter can be made and moulded several days ahead of time.»