Prepare 1.5 liters of rhubarb juice from approx. 2.5 - 3 kg of fresh rhubarb in the juicer and mix with the sugar and the 3 - 4 vanilla sugar. Then add the rum and stir well again.
Then the liqueur is filled into appropriate bottles and doesn`t have to stand that long. But if you want, you can leave it for at least 4 weeks.