01 - In a blender, combine the vanilla ice cream, whole milk, peanut butter, and vanilla extract.
02 - Blend on high until smooth and creamy, about 30–45 seconds. Stop to scrape down the sides if needed.
03 - Taste and adjust the consistency: add more milk for a thinner shake or more ice cream for a thicker shake.
04 - Pour into chilled glasses.
05 - Top with whipped cream, crushed peanuts, and chocolate syrup if desired. Serve immediately with a straw and a long spoon.