Make some espresso. You can also use freshly brewed coffee for a slightly less strong coffee flavor.
Add ice to a shaker. Then add in the vodka, coffee liqueur, and espresso.
Shake vigorously for 10 to 20 seconds. The longer you shake, the more frothy the top of the martini will be.
Strain into a martini glass quickly to ensure the foam comes out and into your drink.