Behold, Lime-cello! There’s limoncello and grapefruit-cello where that came from too. Because I goofed and didn’t share the process with my sister when I was in PDX, I’m sharing it here for posterity’s sake.

Citrus-cello in 10 steps or less (two of which include taste-testing)

1. Buy the highest-proof everclear you can find, and split the bottle in half into two carefully-sterilized 750 ml bottles with cork or plastic stoppers, not screw-on caps (vodka or scotch bottles run through the dishwasher work nicely for this purpose).
2. Add a little more than a cup of citrus zest to each bottle (somewhere around 7 large limes or lemons, or three large grapefruit). For the best flavor, find citrus with extremely colorful peels; the color equates to lovely citrusy flavor. Because I use two bottles for extraction, it’s easy to do two different flavors of citrus-cello with a single bottle of everclear.
3. Let the mix sit for two weeks, shaking the bottle occasionally to redistribute the zest for maximum extraction of goodness.
4. From here on out, treat each bottle separately if you’ve done two different flavors. Strain the citrus extraction into a good glass pitcher with metric measuring marks, and toss the now-crunchy mostly-white zest. Note how much everclear/citrus mixture you’ve got.
5. Grab two new 750 ml bottles, or re-sterilize the two you used during the extraction process. Pour the strained everclear/citrus into one of these bottles.
6. Mix up some simple syrup: 2 parts sugar to one part filtered water, heat until combined, usually just after boiling. (I actually do this in the microwave. Carefully.) Refrigerate until cool.
7. Test your sugar preferences. In a shot glass, measure 1 part everclear/citrus mixture and 1 part simple syrup. Put it in the freezer and let it chill. Taste. If it’s too sweet, add filtered water until you have a citrus-cello you can happily drink, keeping track of the approximate proportions of added water. If it’s not sweet enough, add more simple syrup.
8. Using your personal preferences as a guide, pour the right amount of simple syrup into the bottle already containing your citrus/everclear mixture. Shake to combine.
9. Place in the freezer, and enjoy when chilled.

Because your final product will be somewhere in the 90-proof arena, your citrus-cello probably won’t turn into slush when it’s frozen but will instead remain a lovely syrupy consistency perfect for drizzling over vanilla gelato.