01 -
In a large saucepan over medium heat, combine the rhubarb, sugar, and water. Stir to dissolve the sugar.
02 -
Bring the mixture to a gentle simmer and cook for 20-25 minutes, stirring occasionally, until the rhubarb softens and begins to break down.
03 -
Use an immersion blender (or transfer to a blender) to purée the mixture until smooth.
04 -
Stir in the lemon juice, vanilla extract, and cinnamon (if using). Simmer for another 5 minutes until thickened.
05 -
Remove from heat and allow to cool. Transfer to a clean jar and store in the refrigerator for up to 2 weeks.