In a blender, combine the vanilla ice cream, milk, and vanilla extract.
Blend Until Smooth:
Blend on high speed until the mixture is creamy and smooth. Adjust the consistency by adding more milk for a thinner shake or more ice cream for a thicker shake.
Pour into Glasses:
Pour the milkshake into two tall glasses.
Garnish and Serve:
Top with whipped cream, sprinkles, or a cherry, if desired. Serve immediately with a straw.