SPRAY a 9 inch baking pan with cooking spray. Set aside.
COMBINE milk, sugar and remaining butter in a large heavy saucepan. Cook and stir over medium heat until sugar is dissolved. Bring to a rapid boil; boil for 5 minutes, stirring constantly. Remove from the heat; stir in chocolate chips and marshmallow creme until melted. Fold in the caramels, cashews and vanilla.
POUR into prepared pan. Cool. Once set, cut fudge into 1-in. squares. Store in an airtight container.