Dear Virginia:
This is a recipe I have for mashed potato candy...maybe it will help. You could modify it to use peanut butter instead of the cocoanut. Hope you can use it.
Maggie

2 cups sifted powdered sugar
1/3 cup mashed potatoes (cold)
1 tsp. butter or oleo
1 tsp. vanilla
2 cups unsweetened chocolate melted over hot water

Mix sugar, potatoes, and butter in a mixing bowl. Add coconut, vanilla, and salt, blend well. Press into ungreased pan so candy is one-inch thick.

Pour melted chocolate over the top. Place where it is cool. When firm cut into squares.