Chill your martini glass in the freezer for 5 minutes. Brew espresso and let cool slightly.
Fill a shaker halfway with ice. Add vodka, limoncello, espresso, coffee liqueur, and simple syrup.
Shake vigorously for 15 seconds until well chilled and foamy.
Strain into a chilled martini glass.
Garnish with a lemon twist or a few coffee beans.
Notes
Serve immediately for the best foam. Adjust sweetness by varying simple syrup. Add half-and-half for a creamy version. Balance the coffee intensity by tweaking espresso and liqueur amounts.