Peel the rhubarb and cut into small pieces. Cut the vanilla pod lengthways and scrape out the pulp. Mix the rhubarb, the vanilla pulp and the pod with the preserving sugar (I prefer the tropic preserving sugar because I find it tastier, but it can also be a regular preserving sugar) and let it steep overnight.
The next day add the quartered strawberries and the finely chopped bananas and bring to the boil in a saucepan. Now remove the pod as well, otherwise it will boil over and leave unsightly brown threads in the jam.
Bring the whole thing to the boil for 4 - 5 minutes on high heat according to the package instructions, make the gelling test and pour the jam into clear rinsed glasses (I used 6 glasses of 250 ml each) and allow to cool.