I made this last summer and it turned out very good!  Good addition to vodka cocktails.

2 750-milliliter bottles of 100-proof vodka
2 cups water
2 cups sugar
14 medium lemons with bright, fragrant skins

Microplane grater or serrated vegetable peeler
A one-gallon glass jar for infusing
Large bowl or jar for mixing
Resealable bottles for the finished product

Step 1
Wash and dry the lemons. Remove the lemons’ zest, taking care to avoid the bitter white pith. This is best accomplished with a Microplane grater but you can also use a sharp, serrated vegetable peeler. Save the zested lemons for another use.

Step 2
Place the zest in the glass jar and add one bottle of vodka. Seal tightly and let the mixture steep—shaking it daily—until the peels lose their color and the liquid turns bright yellow and very aromatic, at least two weeks.

Step 3
Strain the infusion through a double layer of moistened cheesecloth into the clean jar or bowl, being sure to squeeze the last drops of intensely flavored liquid from the peel. Add the second bottle of vodka.

Step 4
Combine the sugar and water in a saucepan over medium heat and stir until the sugar is completely dissolved and the syrup just comes to a boil. Remove from heat and let cool.

Step 5
Add the syrup to the infused vodka. For cloudy limoncello, add the syrup while still slightly warm.

Step 6
Using the funnel, pour the liqueur into sterilized bottles, seal tightly and let rest at least one week. Additional aging will result in a smoother marriage of flavors.