If using, drizzle chocolate syrup inside a chilled glass and return it to the freezer.
Add the ice cream, milk, and vanilla extract to a blender and blend for 15-20 seconds until smooth and thick.
Break 8 cookies in half, drop them in, and pulse 4-6 times so they break into small chunks without fully dissolving.
Check the texture: pulse once or twice more for finer pieces, or stir in an extra crumbled cookie for bigger ones.
Pour into the prepared glass and top with whipped cream and the reserved crushed cookie.
