The wide array of uses for the dried zest of lemons, limes, oranges, and grapefruits may not be readily apparent upon first consideration. But if you think of the rinds that end up as waste after juicing and squeezing, and then realize that -- in addition for use in general baking and cooking -- things like citrus powder, citrus extract, citrus sugar, citrus-infused oil, and lemon pepper can all be created from dried zest, then maybe it makes more sense.
If you don’t have a microplane or zester, you can also use the small side of a box grater. Try to scrape just the outer layer, the white layer of pith is bitter. To dry, spread the zest on a towel and leave in a warm, low-moisture area until thoroughly dried. Store in a clean jar.
See 20 Uses for Leftover Rinds and Peels for instructions on the dried zest uses listed above.