1. Use a very sharp knife to thinly slice lemon. (A dull knife will produce unattractive slices.) Pop out any seeds and discard. Bring sugar and water to a boil in a straight-sided skillet, stirring to dissolve sugar. Add lemon slices in a single layer and simmer until rinds are softened, 15–30 minutes. (The longer they cook, the more candied and darker they get.) Transfer to a parchment-lined baking sheet lightly greased with oil. Let stand until ready to use.