Fill a cocktail shaker halfway with ice. Add vodka, coffee liqueur, and limoncello. Shake gently for 10 seconds to blend and chill.
Strain into a rocks glass filled with fresh ice.
Slowly pour heavy cream over the back of a spoon for a layered effect, or stir lightly for a blended look.
Garnish with a lemon twist.
Notes
Use heavy cream for richness or half-and-half for a lighter version. Bump up the coffee liqueur for more coffee flavor. Serve cold for best results. Try it in a martini glass for a more elegant vibe.