Limoncello is an Italian lemon liqueur mainly produced in Southern Italy, especially in the region around the Sorrentine Peninsula and the coast of Amalfi. 
Limoncello is commonly served 'straight', without ice in either a shot glass or tulip tasting glass. Limoncello is poured directly from the freezer, to be consumed freezing cold. This is how you can truly taste the full flavour of the limoncello.