Mother's Melon and Banana Jam

1. Peel and cut the fruit, then cover with one kilogram of sugar over the top. Cover with cling film for about 6 hours.
2. When it has released juice up to the level of the fruit, stir again and put on high heat on the stove until it boils.
3. Then reduce to medium, stirring every 10 minutes. After about 30 minutes, reduce to low so it doesn't burn, stirring constantly. It has started to thicken completely — keep stirring constantly until almost all the water has boiled off.
4. At the very end, before removing it, add a packet of citric acid (лимонтозу), turn off the stove and stir for about 10 minutes, then take off the heat.
5. Pour the boiling jam into washed, dry, warmed jars — the jar must sit on a cloth folded several times and be held with a cloth so you don't scald yourself. Fill, close and leave somewhere on the ground, again on a cloth folded several times.
6. By the next morning the lids should have sunk in. To be safer, wrap them in a blanket so they cool more slowly and vacuum-seal better without exploding.

Note: I sterilize mine — fill the jars, let them cool completely, close them, then sterilize them for about 5 minutes after the water comes to a boil.