Use fruits that are as ripe as possible. Wash, core and eighth the peaches. Peel the bananas and add to the peach pieces. Then puree relatively finely with a hand blender, depending on your taste, small pieces may remain.
Weigh the peach and banana mixture as precisely as possible to the nearest 1000 g and then mix it with 500 g of preserving sugar. Add the vanilla flavor, according to taste 1 packet (hint of vanilla) or 2 packets (strong vanilla taste).
Pour the mixture into a sufficiently large saucepan, as it tends to get very sharp and rise. Cook at the highest setting for 3 minutes while stirring. Observe the information on the preserving sugar pack.
Then fill the jam jars with hot rinsing to the brim, screw tight and turn upside down for 5 minutes.
After a few hours, the jam will be firm and ready to be consumed.