In a large mixing bowl, combine the creamy peanut butter, powdered sugar, softened butter, and vanilla extract. Use a rubber spatula to mix until well combined and smooth. The mixture should be thick but pliable.
Gently fold in the crisped rice cereal until evenly distributed.
Using a cookie scoop or tablespoon, scoop out portions of the peanut butter mixture and roll them into balls about 1 inch in diameter. Place them on a wax paper-lined baking sheet.
Refrigerate the truffle balls for at least 30 minutes to allow them to firm up.
While the truffles chill, melt the milk chocolate chips. Place them in a microwave-safe bowl and heat in 30-second intervals, stirring in between, until completely melted and smooth.
Once the truffles are chilled, dip each truffle into the melted chocolate, ensuring they are fully coated. Allow any excess chocolate to drip off before placing them back on the wax paper.
Allow the chocolate coating to set at room temperature or place the truffles back in the refrigerator for faster setting.
