Life is too short to drink boring lemonade . . . and life is also too short for a lemonade recipe. Enter: this watermelon lemonade sweetened with vanilla bean simple syrup and garnished with a mint sprig. Depending on the ripeness of your fruit, you may need to add more or less sugar and lemon juice, which is why this how-to offers proportions and eyeballed measurements, so you can taste and doctor to your liking.
My favorite method for juicing watermelon is through a chinois strainer. The fine mesh sieve catches the fibrous particles and the wooden pestle makes it easy to squish the juice out of every last bit of watermelon. However, if you don't have this, you can also simply blend up all the watermelon in a blender, then pour the juice through a sieve strainer and into a pitcher.
Then taste! It's probably very tart, but some watermelon is incredibly sweet. It just depends.
Sweeten and stir until the lemonade is sweet enough. Check out those vanilla bean particles.