These go on top of each Poppy-Seed Tartlets with Lemon Curd.
Using a mandoline, cut lemons into thin slices. Place sugar and water in a heavy saucepan. Place over medium-high heat; bring to a boil, stirring to dissolve sugar.
Add lemon slices to sugar water; bring to a second boil. Remove from heat, and let cool to room temperature.
Store refrigerated in a covered plastic container for up to 1 week.