The original recipe is as follows:
1/2 cup Peanut butter (creamy is the best to work with)
1 1/2 cup Sugar
1 tsp. vanilla extract
1/2 cup butter
1 cup flour
Preheat oven to 350 degrees. Mix all ingredients. DO NOT GREASE THE PAN. Bake in a 4 x 12x 2 pan for 25-30 minutes. Cut into squares.
Now as I have said before I have made some changes. They are:
1 cup chocolate chips
I bake in a 9 x 13 pan.
On other occasions I have also added melted chocolate and swirled it in, I have added all kinds of different nuts. Most anything is great mixed in it.