Combine rhubarb, sugar, and water in a medium pot over high heat, stirring constantly until sugar dissolves.
Bring mixture to a boil, then reduce heat to a simmer. Cook until rhubarb is soft and starting to fall apart, stirring frequently (about 5 to 7 minutes).
Remove from heat, then let cool for about 10 minutes.
Place a fine mesh strainer over a large bowl, then transfer rhubarb mixture to strainer.
Stir rhubarb mixture until most liquid has drained into bowl, then firmly press the pulp with the back of a spoon to extract the remaining liquid.
Let syrup cool completely before making lemonade.
Prepare Lemonade:
Combine 1 to 1 ¼ cups syrup (to taste), lemon juice, and 2 cups cold water in a pitcher. Mix well.
Thinly slice reserved peel, then stir into lemonade.
Serve over ice. Enjoy!
Notes
You will have leftover syrup. Use it to make other drinks (like this tasty Rhubarb Soda), or make more lemonade!Customize the sweetness by adding more (or less) syrup, lemon juice, and / or water.Use a food scale to weigh the rhubarb, if you have one. You'll get a more accurate measure of the amount than you would with cups. This is the scale that I use (and highly recommend).Don't throw out the rhubarb pulp when making the syrup. It makes a delicious "jam" that's wonderful on toast, bagels, and more!Check out the info before this recipe card for more tips, variations, and related recipes!