Prepare the Rhubarb - Start by washing the rhubarb stalks thoroughly. Then, chop them into small pieces, about 1-inch in size.
Cook the Rhubarb - In a large saucepan, combine the chopped rhubarb with 2 cups of water. Bring the mixture to a boil over medium-high heat, then reduce the heat and let it simmer for about 10-15 minutes, or until the rhubarb is very soft and breaks down easily.
Sweeten the Rhubarb - Add 1 to 1.5 cups of sugar to the saucepan (depending on your sweetness preference). Stir well until the sugar is completely dissolved. Taste the mixture and adjust the sweetness if needed.
Strain the Rhubarb - Remove the saucepan from heat. Using a fine mesh strainer or cheesecloth, strain the rhubarb mixture into a large bowl or another saucepan, pressing down to extract as much liquid as possible. Discard the solid remnants left in the strainer. Let the rhubarb syrup cool to room temperature.
Juice the Lemons - While the syrup is cooling, juice your lemons until you have about 1 cup of freshly squeezed lemon juice.
Combine and Mix - In a large pitcher, combine the cooled rhubarb syrup with the lemon juice. Add the remaining 2 cups of water to dilute the mixture. Stir well to ensure everything is mixed evenly.
Chill the Lemonade - If you have time, refrigerate the lemonade for at least an hour to let the flavors meld together.
Serve - To serve, fill glasses with ice and pour the rhubarb lemonade over the top. Garnish with lemon slices and fresh mint or basil if you like.
Enjoy! - Sit back, relax, and enjoy your refreshing homemade rhubarb lemonade! It's perfect for a hot summer day or any time you need a delicious, thirst-quenching drink.