1. In a large frying pan, combine the sugar, juice of one lemon, and water. Bring to a boil over medium heat, stirring until sugar is dissolved. (The result will be a lemon simple syrup.)
2. Lower heat to a simmer. Add lemon slices from the second lemon in a single layer and cook about 15 minutes. Turn slices occasionally.
3. Using tongs, transfer the lemon slices onto Gefen Parchment Paper to cool. Set aside, reserving the lemon simple syrup for the duck glaze.