Blend base. Add the vanilla ice cream and ½ cup of milk to a blender. Add the cookies. Secure the lid and blend on high speed for about 1 minute, or until smooth.
Add color. Remove the lid and add a few drops of blue food coloring. Blend again until evenly colored. Add more food coloring, a drop at a time, until the desired shade is reached.
Serve. Pour into a drinking glass. Serve immediately and enjoy.
Notes
Consistency Tip. Add more milk for a thinner milkshake or a handful of ice for a thicker texture.
Scaling. This recipe doubles or triples easily for multiple servings.
Decorative Rim Idea. For a fun presentation, coat the rim of the glass with chocolate frosting and press into crushed cookies before pouring in the milkshake.