Ensure the butter and peanut butter are at room temperature before you start.
Preheat the oven to 170C Bake. Line a baking sheet with greaseproof paper.
Place the butter, peanut butter and sugars into a large bowl and beat using an electric beater for 3-4 minutes until very smooth.
Break in the egg and add the vanilla, then beat again for another minute.
Roughly chop the chocolate and stir this in to the butter mixture.
Sift on the flour, baking powder and soda, and stir to combine.
Roll large tablespoons of the mixture into balls between your hands and place them onto the prepared baking sheet, leaving a 3 inch gap between each ball.
Press each ball gently with your fingers until you have a 1.5 inch high circle of dough.
Bake for 12-14 minutes until lightly browned. Remove from the oven and use a metal spatula to transfer the cookies immediately to a wire rack to cool.
Notes
This is a soft cookie dough and it will spread quite a bit during baking, so be sure to leave space between your cookies on the baking sheet.
If you can't find dark cane or muscovado sugar, replace with soft brown sugar.
Likewise, if you can't source vanilla bean paste substitute vanilla extract, though a quality paste will give you a superior flavour.
Recipe by The Fare Sage at https://www.thefaresage.com/peanut-butter-cookies/