1. Peel the bananas and weigh the net amount.
2. Add an equal weight of sugar along with the lemon juice. 
3. Grate the chocolate.
4. Cook the jam until the desired cooking stage is reached.
5. Add the chocolate to the jam.
6. Stir until the chocolate has melted. The consistency should be fairly thick. 

Finishing

1. Pack the jam into sterilized jars. 
2. Add 1 tbsp. rum per jar before sealing. 
3. Close up and turn upside down until completely cooled. 
4. Label and cover with parchment paper.