HEAT oven to 350F. Coat 13x9-inch baking pan lightly with no-stick cooking spray.
MELT 2 cup chocolate chips and 1/2 cup butter in medium saucepan over low heat, stirring until smooth. Remove from heat.Add sweetened condensed milk and vanilla. Stir in flour. Spread in prepared pan. Bake 12 to 15 minutes or until set. Cool.
MELT 1/4 cup butter in medium saucepan over medium-high heat. Stir in sugar and 1/4 cup cream. Boil 5 minutes. Remove from heat. Stir in marshmallow cream, 1/4 cup peanut butter and peanuts. Spread evenly over baked layer. Cool.
COOK caramels and 1/4 cup cream in small saucepan over low heat, stirring until caramels are melted. Spread over marshmallow layer. Cool until set.
COMBINE 1 cup chocolate chips, butterscotch chips and 3/4 cup peanut butter in small saucepan. Cook and stir over low heat until melted. Spread over caramel layer. Chill 30 minutes or until set.