Place the Oreo cookies in a zip-top bag and gently crush them with a rolling pin.

Pour the milk into the blender first to help the blades move smoothly.

Add the vanilla ice cream to the blender.

Add the crushed Oreo pieces.

Add the vanilla extract if using.

Blend on medium until smooth and creamy — start with short pulses, then blend fully.

Taste and add a little more milk if you prefer a thinner consistency.

Pour into tall glasses.

Top each shake with a swirl of whipped cream.

Drizzle chocolate syrup over the whipped cream and press a whole Oreo into the top as garnish.

Serve immediately with a straw and long spoon.