01 -
Rinse the rhubarb and trim the ends. Slice it into 1-inch pieces and put it in a heavy-bottomed pot along with the sugar. Add 2 tablespoons of water and the lemon juice, and stir to combine.
02 -
Heat, stirring constantly, until the rhubarb starts to release juice and the mixture comes to a boil. Boil gently for about 15-20 minutes, until the rhubarb is soft and mostly broken down.
03 -
Puree the mixture in a blender or food processor until smooth. Be cautious when pureeing hot foods; make sure the lid is secure and vented.
04 -
Return the puree to the stove and bring to a boil. Reduce the heat to a gentle simmer, allowing it to thicken and reduce while stirring frequently. Cook for about 20 minutes until the mixture darkens, becomes glossy, and thickens further.
05 -
Transfer the finished butter into a glass jar. Let it cool completely, then cap and refrigerate. The butter will thicken more as it chills. Yields approximately one and a half cups.