Wash the currants and gooseberries. Strip currants from the panicles. Put berries in a pot, add 250 ml water. Bring to the boil covered and simmer for about 10 minutes. Press the compote through a sieve and collect the juice. It should produce 1 litre juice, let it cool down.
Mix juice, vanilla sugar and jam sugar in a large pot. Boil for 2-4 minutes while stirring constantly (gelling test!). Skim off any foam from the jelly. Fill jelly immediately into hot rinsed glasses with twist-off lids and close them tightly. Place the jars on the lids for about 5 minutes, turn them over and let them cool down.