Place the Oreos in a plastic bag and gently crush them with a rolling pin or the bottom of a glass until finely chopped but still with some chunks for texture.
Add the crushed Oreos, milk, and ice cubes into a blender.
Secure the lid of the blender and blend on high speed for about 30-45 seconds until the mixture is smooth, icy, and creamy with small cookie bits visible.
Stop the blender and check the consistency; if it's too thick, add a splash of milk and blend briefly to loosen it slightly.
Pour the slushie into glasses, allowing some ice and cookie pieces to stay suspended for texture.
If desired, garnish with some whole or halved Oreos on top for extra crunch and visual appeal.
Serve immediately with a straw and enjoy this frozen, nostalgic treat.
