1 box of yellow cake mix
1/3 cup plus 1/4 cup melted butter or margarine, divided
3 cups mini marshmallows
1 cup light corn syrup
1 1/2 cups peanut butter chips or butterscotch chips
3 teaspoons vanilla
3 cups rice crispy cereal
3 cups salted peanuts or salted cashews
Preheat oven to 350. Beat cake mix, 1/3 cup melted butter and egg in a medium bowl. Press mixture into an ungreased 9x12 glass baking dish. Bake until lightly browned, about 12 minutes. Sprinkle on your marshmallows and bake for another 10 minutes or until marshmallows are all puffy. Let cool.
Combine corn syrup, remaining butter and peanut butter chips in a large saucepan. Cook over medium heat, stirring frequently, until chips are melted, about 5 minutes. Stir in your vanilla. Add the cereal and peanuts, mix well. Spread over slightly cooled marshmallows. Cool completely before cutting into bars. Store in an airtight container.