01 -
Let everything chill until it's room temp. Pop both the sweet rhubarb and syrup into a tight-lidded container. Tuck in the fridge for up to a week, or freeze if you want it to last longer.
02 -
Turn the burner to medium-low once it boils. Keep cooking for another 20–25 minutes without a lid, giving it a gentle stir here and there. It's ready when the rhubarb goes soft and see-through, and the syrup thickens just a bit.
03 -
Bring the pan to a boil on medium-high. Stir every so often so nothing gets stuck to the bottom.
04 -
Toss the lemon juice, rhubarb, sugar, and water in a medium pot. Stir them together carefully so everything gets coated.