Ready in 30 minutes
In a mixing bowl, cream butter, peanut butter and sugars. Beat in egg and vanilla. Stir in flour until blended.
Spread dough onto a greased 12-in. pizza pan. Bake at 375 degrees F for 12 minutes. Sprinkle with marshmallows and chocolate chips. Bake 5-6 minutes longer or until lightly browned.