A great tasting limoncello starts with freshly harvested organically grown lemons. Wash them. Using your favorite tool for zesting, remove just the thin yellow skin, or zest, of the fruit.
Combine the lemon zest and vodka in a large glass jar, secure a lid, and let sit for at least 1 and up to 3 weeks. See Recipe Note below for the options with 12 zested lemons.
After infusing the vodka for 1 to 3 weeks, prepare sugar syrup. In a pan, combine water, lemon juice, and sugar and bring to simmer until sugar is completely dissolved. Take it off the heat and let cool to the room temperature.
Add sugar syrup to infused vodka and stir. Cover and let it sit for 1 to 3 days, then strain and bottle. Refrigerate limoncello for at least 1 day before serving.