[header] How to make rhubarb butter [title] Wash the rhubarb thoroughly. [step] Slice off the broad green leaves and the ends of the stalks. Place the rhubarb stalks in a colander or grip a bunch loosely in one hand and run them under a stream of cool water. 
Scrub off any visible dirt and remove damaged or discolored spots with a paring knife. [substeps] Fresh rhubarb can be found seasonally (late spring to early summer) at most supermarkets and specialty food stores.