We will start cutting into pieces or watermelon , if possible seedless watermelon, and set aside 1/2 cup of cut watermelon.
Prepare your lemon juice, at least 1/2 cup and strain it to move away the seeds, and set aside.
Using your mixer glass or kitchen robot, place the chopped watermelon, a cup of water, the lemon juice, and sugar or sweetener.
Grind the watermelon until you have watermelon juice.
With the help of a strainer move away the seeds and the watermelon pulp, this way you will extract the watermelon juice, that you can pour in your lemonade jar.
Add to the lemonade jar 2-3 water cups and ice.
Taste the watermelon lemonade to adjust the sweetness and add more sugar or sweetener if needed.
Serve with lots of ice, mint, a lemon slice, and enjoy!