01 -
Thoroughly wash rhubarb stalks, discard any rhubarb leaves, and slice into 1.25 cm pieces using a clean knife and cutting board.
02 -
Scrub lemons under running water, grate zest using a fine rasp or grater, then halve lemons and extract juice with a handheld juicer or fork. Strain to remove seeds and combine juice with chopped rhubarb.
03 -
In a medium saucepan, combine water, granulated sugar, the rhubarb-lemon mixture, and lemon zest. Set over medium-high heat and bring to a boil. Cook for 20 minutes, stirring occasionally, until rhubarb becomes soft and breaks apart.
04 -
Remove pan from heat and gently mash the mixture to release maximum flavour. Let cool for 10 minutes, then strain through a fine sieve into a large bowl, discarding solids.
05 -
Mix 1 part rhubarb-lemonade concentrate with 3 parts cold water. Serve over ice with lemon slices if desired.