Now to make the filling. Pour the milk in to a saucepan heat up slowly it is prone to burning so be careful). In a separate bowl combine your egg yolks, sugar, orange blossom and vanilla whisk it together. Now pour over the hot milk, whisking all the time. It will thicken, you want it very thick, again careful not to burn it. Now allow it to cool. In the meantime, whisk the cream, then whisk in the custard mixture. If you are not using straight away be sure to cover with cling film touching Crème Pâtissière. Slice the eclairs in half lengthways, pipe in your Crème Pâtissière and place the lid on.