01 - Add vanilla ice cream, whole milk, peppermint extract, vanilla extract, and green food coloring to a blender canister.
02 - Process on high speed until completely smooth and creamy, approximately 30–45 seconds. Add additional milk 1 tablespoon at a time if thinner consistency is preferred.
03 - Taste the mixture and modify peppermint extract or food coloring as needed. Peppermint extract is potent, so add sparingly.
04 - Divide the shake evenly between two tall glasses, filling nearly to the rim.
05 - Top with whipped cream, maraschino cherry, and green sprinkles if desired. Serve immediately while cold.