01 -
Trim and cut the rhubarb stalks into small pieces.
02 -
Combine chopped rhubarb and water in a large saucepan. Bring to a simmer over medium-high heat and cook for approximately 10 minutes or until the rhubarb is very soft.
03 -
Pour the cooked mixture through a fine mesh strainer into a medium saucepan, pressing firmly to extract as much liquid as possible. Discard or reserve the solids.
04 -
If using a vanilla pod, add both seeds and pod to the saucepan with the strained liquid. Stir in lemon juice, zest, and granulated sugar.
05 -
Bring the mixture to a gentle simmer over medium-high heat. Cook for 10–15 minutes, stirring regularly, until it thickens to a syrup-like consistency. Remove the vanilla pod if used.
06 -
Pour the hot cordial into a sterilized jar, seal tightly, and allow to cool at room temperature.
07 -
To serve, dilute 1 part syrup with 4 parts cold water or sparkling water and add ice cubes to taste.