Spread chocolate syrup on one plate and crushed peanut butter cups on another to prepare the glass.
Dip the rim of your martini glass into the chocolate syrup, then press into the crushed peanut butter cups until well-coated.
Fill a cocktail shaker halfway with ice.
Add chocolate liqueur, peanut butter barley tea, white grape juice, and heavy cream into the shaker. Shake vigorously for 15-20 seconds.
Drizzle chocolate syrup inside the chilled glass in a swirl pattern.
Strain the cocktail mixture into your prepared glass and garnish with a mini peanut butter cup or crushed candy.