For the sponge: pre-heat the oven to 180C/gas 4. Grease six dariole moulds with butter and dust with a little caster sugar.
2. Melt the butter in a pan and add the flour, stirring to form a smooth paste or 'roux'.
3. Place the poppy seeds and vanilla into the milk and warm gently over a low heat. Remove the vanilla pod, if using.
4. Little by little add the milk mixture to the roux stirring until all the milk has been absorbed. Tip the mixture into a bowl and add the 6 egg yolks one at a time, beating in to blend thoroughly.
5. Whisk the 6 egg whites incorporating a slow stream of sugar, as if you were making meringue. Once whisked to a soft peak add a quarter of the egg yolk/roux mix and beat into the egg white mix, then fold the rest in very carefully.
6. Spoon the mix into the prepared moulds and stand them half submerged in water in a roasting tray. Transfer to the pre-heated oven and cook for 25-30 minutes.
7. For the orange syrup: mix the orange juice, caster sugar and orange zest in a pan and stir until the sugar has dissolved. Bring to the boil and reduce until syrupy.
8. For the liqueur orange casserole: combine the sugar, water and liqueur in a pan and stir until the sugar dissolves over gentle heat. Increase the heat and cook until it becomes a light syrupy consistency. Add the oranges and leave to cool.
9. To serve, place a little of the orange casserole onto a plate and top with a de-moulded sponge. Pour orange syrup over the top of the sponge and serve.