It's deceptively simple to make, but may take a bit of practice to get just right. It also takes a touch of preparation...

The first step is to put the Limoncello bottle into your freezer. (Don't worry, under normal settings the high alcohol will prevent it from freezing/breaking the bottle.) I'd recommend simply storing your Limoncello this way all the time -- it's lovely when served chilled.

Start by pouring Frambelle into the glass. Ideally use a narrowish funnel-shaped cordial-style glass, preferably smallish as this drink will have about 20-25% alcohol. Fill it about one third full of Frambelle.

Here's the tricky part -- very slowly, pour the Limoncello down the side of the glass. You may need to use your other hand to tip the glass somewhat. (People used to pouring a beer with a good head seem to already have the knack for this.) Slowly, gently, add about 1/3 glass of Limoncello. The Limoncello will go to the bottom of the glass, displacing the Frambelle upwards in a nice clean line.

If the Limoncello is not cold, if you pour the Limoncello too rapidly, or if you simply pour the Limoncello into the glass you'll still have a lovely tasting drink, you simply won't get the attractive layering.