Prep. time: 15 minutes
Cooking time: 35 minutes

1. Peel the bananas and weigh the net result.
2. Dice the pineapple flesh and weigh the net result. 
3. Add an equal weight of sugar and the juice of 1 lemon.
4. Simmer everything for 30 minutes, stirring often until the sugar is entirely dissolved. The mixture should be fairly thick. 

Finishing

1. Pack into sterilized jars. 
2. Add 1 tbsp. rum to each jar before sealing. 
3. Close tightly and leave upside down until completely cool. 
4. Label and cover the jars with parchment paper.