In a large bowl, mix together the butter, shortening, and peanut butter.
Add the brown sugar and granulated sugar. Beat for 2-3 minutes until light in color and fluffy in texture.
Beat in the eggs and vanilla for 1-2 minutes.
In a separate bowl, combine the flour, baking soda, baking powder, and kosher salt. Add to the mixing bowl and stir until combined.
Scoop 9 balls of dough onto a parchment-covered baking sheet using a #40 dough scoop (about 2 tablespoons) and use a fork to flatten the balls making a crosshatch pattern on top.
Bake at 350˚F for 8-11 minutes. Cool for a couple of minutes on the baking sheet and then transfer to a wire rack to cool completely.
Continue scooping the dough and baking the cookies allowing the baking sheets to cool between batches.
Video
Notes
Store peanut butter cookies in an airtight container or ziptop bag at room temperature for 3-4 days or in the freezer for 3-4 weeks.