Begin by rolling four fresh lemons on a flat surface; this helps maximize your juice extraction. Cut each lemon in half and juice them until you have one cup of fresh lemon juice. Aim for a vibrant yellow color, and set the juice aside in a large pitcher.

In the same pitcher, add the freshly squeezed lemon juice to one can of sweetened condensed milk. Using a whisk or a sturdy spoon, stir the mixture vigorously until all lumps disappear, creating a smooth base.

Gradually pour in two cups of ice-cold water into the pitcher while continuously stirring to ensure an even mix.

Taste your lemonade. If you desire a sweeter flavor, mix in a few tablespoons of simple syrup until you reach your desired balance.

Refrigerate your mixture for about 30 minutes to chill, or serve immediately over ice cubes, garnishing with lemon slices and mint leaves.