Bring your water to a boil.

Make a hibiscus lime sugar by grinding up your hibiscus flowers, vanilla extract (or juice from one lime), and zest from a lime into your sugar. I do this in a mortar and pestle, but a food processor or blender works as well!

Squeeze limes into a large jar or pitcher. Strain to remove any seeds.

Add your hibiscus lime sugar and boiling water. Stir to let the sugar dissolve.

Chill and serve over ice.