Makes just under 4 quarts
1 liter (33.8 ounces) pure alcohol, or 4 1/4 cups*
8 3/4 cups whole milk
5 pounds sugar (10 cups)
1 shot glass whiskey
1 teaspoon pure vanilla extract
*We use Everclear, which comes in 750 ml bottles. You will need to buy two bottles of Everclear for this recipe, but you'll use only about 1 to 1 1/2 cups of the second bottle.
Peel lemons and oranges, being careful not to include any white pith or pulp. Place peels in a bowl and cover with alcohol. Soak for 1 week on the countertop.
After a week, strain lemon and orange alcohol and discard peels. Pour into a heavy-bottomed, large saucepan. Add milk, sugar, whiskey and vanilla. Bring to a boil, then reduce until just bubbling and cook for 5 minutes. Stir continuously, and keep a close eye on it so it does not boil over. Remove from heat and let cool completely. A thin film will form on top of the limoncello. Skim it off and discard, then pour thorough a fine mesh sieve.
Pour into bottles and freeze. Keep in freezer at all times. Shake before using.