Slice off the end of the lemons with a sharp knife.
Cut the peel off the lemons in a spiral while making sure to cut as little of the white off of the lemon as possible. They should be very thin.
Place the rind layers in the container and pour the pure alcohol over the lemon rinds.
Tighten the lid to prevent evaporation and let the alcohol marinate for 15 days.
Shake the mixture periodically to let the ingredients incorporate then place the container in a dark place.
Boil the ½ gallon of milk for 20 minutes and remove milk skin from the surface.
Add sugar to the milk and let the sugar melt then stir sugar in with the boiling milk to let it incorporate.
Place the lid over the milk and let it completely cool down the milk once the sugar has melted then add a spoonful of vanilla.
Once crema mixture is cool, pour marinated alcohol through a strainer into the pot to prevent the rind from falling in.
Stir mixture together then spoon a small amount into a container to mix around and pour to extract all remaining alcohol.
Stir the mixture with a wooden spoon then bottle it with a ladle and funnel before placing them in the freezer.
Leave space in the bottle for the mixture to expand – in other words, don’t fill them to the all the way to the top.
Let the mixture freeze while periodically moving bottles around to incorporate the limoncello.
Remove bottles from the freezer and pour them into small shot glasses.
Limoncello will keep in the freezer for more than a year – if you let it last that long.