Fill a cocktail shaker about halfway with ice cubes.
Add vanilla vodka, crème de cacao, Irish cream liqueur, and chocolate liqueur.
Drop in the scoop of vanilla ice cream.
Shake hard for about 15 seconds until very cold and creamy.
Strain into a chilled cocktail glass.
Top with whipped cream and a drizzle of chocolate syrup, if desired. Serve immediately.
Notes
Use quality vanilla vodka for a smoother sip. Dark crème de cacao gives deeper chocolate notes; white keeps it lighter. For an even fluffier texture, blend instead of shaking. Chill the glass first to keep the drink thick and cold.