For the simple syrup, combine 1 Cup Sugar and 1 Cup Water in a small saucepan over medium heat. Boil for 5 minutes until sugar is dissolved. Cool completely.
Preheat a grill pan or grill until very hot. Oil lightly to prevent any sticking.
Halve the lemons and sprinkle the cut sides with a small amount of sugar. Place cut side down on the grill pan and cook for 2-3 minutes and remove to a plate until cool enough to handle. Squeeze the juice from them while still warm into a strainer over a measuring cup. You'll need 1 full of Cup of lemon juice.
Also, make thick slices from another lemon (or two) and sprinkle both sides with sugar. Grill until marks appear, repeat on the other side. Set aside for garnish.
Add the lemon juice to a pitcher. Follow with the simple syrup, 4 Cups of Water and Ice Cubes.
Makes six 8 oz. servings.