Combine the water and brown sugar in a small saucepan with a lid.

Bring to a boil, stirring to dissolve the sugar. Add the lemon zest, then set the plums in the bottom of the pan, reduce the heat, cover, and simmer for 10 minutes.

After 10 minutes, remove the lid and continue simmering for about 8-10 minutes, until the liquid has thickened.

Turn off the heat and allow the plums to cool for about 5 minutes. Serve in individual bowls, topped with vanilla ice cream and drizzled with the brown sugar syrup.