In a mixing bowl beat the butter on medium-high speed for 30 seconds. Add peanut butter and sugars. Beat until fluffy. Beat in the eggs and vanilla until combined. Add the dry ingredients and beat until well mixed.
Preheat oven to 375º. Shape dough into 1 1/4-inch balls. Roll balls in additional granulated sugar to coat. Place balls 2 inches apart on an ungreased cookie sheet. Using the tines of a fork, flatten balls by making crisscross marks on top. Bake for 7 to 9 minutes or until bottoms are light brown. Transfer to a wire rack and let cool.
Layer cookies between waxed paper in an airtight container; cover. Store at room temperature for up to 3 days or freeze for up to 3 months.