Slightly grate bitter oranges to remove the red colour which covers their
skins. Without cutting the flesh itself, cut the peel off the oranges
divided to four.
Remove the white pith from the inside of the skin and
roll them. Tie with a strong string so that they remain rolled while
cooking. Then place in a glassbowl of cold water and leave for 3-4 days.
Change the water daily. On the fourth day, place them into a large pan
of boiling water. Cook for 20 minutes until they are soft. Drain them
Into a separate saucepan pour 3 cups of water and 1.5 kg sugar. Place
the pan on heat and stir until the sugar is completely dissolved. When
it starts to boil, add in the rolled skins and cook for 40 minutes until
the syrup thickens. Shortly before removing the pan from the heat add
lemon juice and the vanilla sugar. Let it cool and then transfer into
dry jars with lid. Store in cool place for up to one year.