Whisk orange juice with sugar as well as the vanilla sugar, heat gently while stirring until the sugar is completely dissolved, then cool. Brush the orange and lemon thoroughly under hot water. Cut the peels very thinly into small pieces. Squeeze the juice of both fruits and add to the juice-sugar mixture form. Put the peels and spices in a bottle, pour the juice and gin over them and leave to mature, well closed, for a week in a cool dark place, but not in the refrigerator. Pour the mixture through a hair sieve at the beginning and then through a filter. Keep cool.
Shelf life is about 3 months.
Tip: Cook only with high quality spices – they are the be-all and end-all in a good dish!