Begin the preceding night by squeezing the lemons into a strainer formed by placing a coffee filter in a strainer. Strain the lemon juice into a small bowl containing the cold water - this is a very slow (drop-by-drop) process. Add the sugar the next morning. Mix very well with a wooden spoon until the sugar is completely dissolved. Pour into a tin or aluminum pan. Place the pan in the freezer. Let rest for about 5 hours, breaking up the solid layer of ice which forms at least once every hour. Remove the pan from the freezer. Cut the ice into pieces with a knife. Place the ice pieces in an ice crusher (or into a blender running at lowspeed). The ice should form a smooth consistent texture of imperceptible grains (almost like ice cream - no large grains or chunks). Transfer to individual
serving glasses.
