You can also puree the mango if you prefer a smooth jam.
In a thick bottomed saucepan, heat the diced/ pureed mango with the lime juice, zest and cinnamon stick.
Bring to a boil until sugar dissolves .
Then simmer while stirring often until the mixture thickens.
To check if it is thick enough - put a spoon into it , and rub your finger on the back of the spoon, it leaves a clear path in the jam
Remove the cinnamon stick , let cool and store in the refrigerator
Notes
This lasts for about 10-14 days in the refrigerator in an airtight jar. The jam will thicken further as it cools. For a stronger cinnamon flavour, you can use powdered cinnamon instead. The cup I use for measuring is 240 ml.