In a mixing bowl combine the flour, baking powder, and salt and set aside.
In a stand mixer with paddle attachment, on medium-high speed, beat the butter until smooth. Add the peanut butter and beat until smooth.
Add the sugars and continue to beat until evenly mixed. Add the eggs one at a time waiting a minute between the eggs. Add the vanilla.
Reduce the speed to low and add the flour mixture. Only mix until all of the ingredients are incorporated. Transferred to the mixing bowl, cover, and refrigerate for 30 minutes.
Preheat the oven to 350°F or gas mark 4.
Using a cookie scoop roll out 2 tablespoons of dough and roll into a ball. If you are rolling the dough in sugar then place on the lined sheet pan. Using a fork or bottom of a glass flatten the cookie dough. Dip the fork or glass bottom in sugar after each impression.
Bake for 12-15 minutes or until the edges start getting darker in color. Allow to cool for 2 minutes and transfer to a cooling rack.