Preheat the oven to 325F. Line cookie sheets with parchment paper.
In the bowl of an electric mixer fitted with the paddle attachment, cream the peanut butter with the butter and sugars until light and fluffy. Beat in the egg.
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt. Add the flour mixture to the peanut butter mixture and mix until combined. Do not over mix dough after flour mixture is added.
Scoop dough by the rounded tablespoonful and roll into balls. Roll in granulated sugar. Place the balls about 2 inches apart on the prepared cookie sheets, and press down slightly. Bake for 10 minutes, or until lightly golden. Do not over bake. After removing from oven sprinkle with additional sugar.
Notes
-This recipe needs to be doubled! The original only made about one dozen large cookies.