Wash the lemons and peel off all the zest using a vegetable peeler. Set the peeled lemons aside. Place the lemon zest in a bowl and cover it with sugar. Toss to combine. Cover and let it sit for a minimum of 2 hours, or up to overnight.

Bring water to a boil in a pot over high heat. Turn off the heat and pour in the lemon-sugar mixture. Stir and let it sit until the sugar is completely dissolved, about 5 minutes.

Pour the mixture through a mesh strainer back into the same bowl and discard the zest. Let it cool to room temperature, which takes about 20 to 30 minutes.

Cut the lemons in half and squeeze the juice into the bowl. Pour the lemonade into a serving pitcher, cover, and chill thoroughly before serving over ice, at least 2 hours.