Melt butter on stove top on low heat. Once butter is melted add the peanut butter and stir till smooth. Then add the cocoa powder and mix well, be careful not to burn. Slowly add the powdered sugar, stirring constantly, until mixture becomes hard to stir.
When mixture becomes hard to stir, remove from heat. Slowly add the remainder of sugar. Mix vanilla in well. Pour mixture from the pot to a baking pan, and smooth into a layer.
Refrigerate 1 1/2 hours. Cut into squares and enjoy!!