In a bowl, cream butter and sugar. Add egg yolks and vanilla; mix well. Combine flour, baking powder, salt and baking soda; add to creamed mixture and mix well. Press into a greased 13x9-in. baking pan. Bake at 350° for 12-15 minutes or until golden. Sprinkle with marshmallows return to oven just until marshmallows begin to puff, about 2 minutes. Cool. Meanwhile, combine corn syrup, butter, chips and vanilla in a large saucepan; cook and stir over low heat until chips are melted and mixture is smooth. Remove from the heat; stir in cereal and peanuts. Evenly spread warm topping over marshmallow layer. Refrigerate until set.