1 cup sugar
2 lt (8-10 cup) water
Wash the lemons and slice them finely with the skins. Place one layer lemon slices on the bottom of a wide bowl. Then spread half of the sugar on them. Then put another layer of sliced lemons and spread the remained sugar on top. Cover the bowl with plastic wraps; make sure it is air and sun light tight.
Leave it all night long (10-12 hours). In the morning, you will see that the sugar is dissolved in the lemon juice. Then with a food processor smash the lemon slices with their skins. Add 8-10 cups of water and mix. Strain the mixture to remove the skins.
You can also adjust the sugar amount at the end. Serve lemonade cool with some ice.
P.S: To prevent the loss of Vitamin C, keep your lemonade covered and cool. Do not leave it under sun light. Do not use metal spoon to mix. Consume in 30 minutes after serving.