2 bottles (750 ml) 100-proof vodka or grain alcohol
4 cups sugar
5 cups water
Wash and dry the lemons.
Zest lemons, making sure not to cut into the pith.
Combine one bottle of vodka and the zest to a 1-gallon mason or other glass jar. Save vodka liquor bottles and clean them thoroughly for later re-bottling.
Store the infusion in a cool, dry place 2-4 weeks. The longer the zest sits in the vodka, the more vibrant the color of the liquid. next step (after 2+ weeks):
Combine sugar and water in a pan and bring to a boil; cook until thickened to make a simple syrup. Let this mixture cool and add to the limoncello mixture.
Add the additional bottle of vodka, and let sit for another 2 weeks. Step 3 (2 weeks later...):
When done aging, strain out the lemon zest and bottle the limoncello in the reserved vodka bottles.
Keep the limoncello in the freezer and serve icy cold. Other uses:
Add to a vodka tonic for extra zing!
Add limoncello to a fresh mint mojito to make a lemon mint mojito.