Blueberry compote (sauce)
Put the blueberries, lime zest, lime juice, cinnamon, salt, and sugar in a medium pot, and bring to a boil.You can add the sugar a little at a time to gauge the sweetness level. A lot will depend on the sweetness of the blueberries.
Make a paste with the cornstarch and a tsp of water. Add to the sauce and remove from the heat right away. Boil for 1-2 minutes. The cornstarch will thicken the sauce. However, you can add more or less to vary the thickness.
Serve or cool
The sauce can be served immediately, or you can cool it. It is best to cool the sauce for cheesecake or ice cream. To cool, leave it at room temperature for 30 minutes, put in a sealed container and store in the fridge for up to 3 days.