For the banana-cherry jam, wash, clean and pit the cherries and boil them with water for a quarter of an hour.
Line a sieve with a kitchen towel and strain cherries in it. Collect the juice.
Peel bananas and mash them with a fork. Mix Gelfix with sugar and add cherry juice, mashed bananas and eggnog. Bring mixture to a boil while stirring and boil for about 1 minute.
Rinse jam jars hot, fill with the banana-cherry jam and close tightly.