By Carroll Pellegrinelli, About.com http://baking.about.com/mbiopage.htm

This peanut butter fudge is not only simple to make but it is tasty too.
Ingredients:

* 1/2 pound (2 sticks) butter
* 1-18 ounce jar crunchy peanut butter
* 1 pound box powdered sugar

Preparation:
Lightly grease an 8 x 8 foil-lined pan. Melt butter and peanut butter in top of double boiler. Stir until melted. Stir in powdered sugar. Stir until smooth. Quickly pour in prepared pan. Once cool, remove foil and fudge. Dump-out on cutting board and cut.

-from: http://baking.about.com/od/fudge/r/easypeanutbutte.htm