Wash the lemons thoroughly and slice them into thin rounds, removing any seeds.

In a saucepan, combine the water and 1 cup of sugar. Bring to a boil over medium heat, stirring until the sugar dissolves.

Add the lemon slices to the boiling syrup and reduce the heat to low. Simmer for about 45 minutes until the lemons are translucent.

Using a slotted spoon, remove the lemon slices from the syrup and place them on a parchment-lined baking sheet. Sprinkle the remaining sugar over the slices and let them dry for at least 30 minutes.