01 -
Drizzle chocolate syrup along the inside walls of chilled serving glasses and place them in the freezer for several minutes to set.
02 -
Combine vanilla ice cream, milk, chocolate sandwich cookies, mint extract if using, and green food coloring in a blender. Blend until smooth and uniformly green, scraping down sides as needed. Add more milk by tablespoons if a thinner consistency is desired.
03 -
Pour the milkshake into the prepared glasses. Top generously with whipped cream, sprinkle with crushed cookies, and finish with a drizzle of chocolate syrup.