Heat the oven to 375 Degrees F. Roll out the cookie dough onto a 12-inch pizza pan. Bake for 12 to 13 minutes or until golden brown. Let cool until cold to the touch. In a small bowl, combine the peanut butter, cream cheese, sugar, salt, margarine, milk and vanilla. Beat on medium speed, of an electric mixer, until light and fluffy. Spread the mixture on the cookie and sprinkle with the chopped peanuts. Cut into wedges.