In a large saucepan, combine the chopped rhubarb, granulated sugar, and water.
Bring the mixture to a boil over medium-high heat, stirring occasionally. Reduce the heat to low and simmer for 20-25 minutes, or until the rhubarb is tender and the syrup has thickened.
Stir in the vanilla extract.
Using a slotted spoon, carefully remove the rhubarb pieces from the syrup and spread them in a single layer on a parchment-lined baking sheet.
Let the candied rhubarb dry for at least 1-2 hours, or until slightly firm. You can also bake them in a very low oven (around 200°F / 95°C) for about 30 minutes to speed up the drying process.
Once dried, the candied rhubarb can be stored in an airtight container at room temperature.
Notes
Enjoy your homemade candied rhubarb! It's delicious on its own, as a topping for ice cream, or in pies and tarts.