Step 1

Preheat oven to 350°F. Line baking sheets with parchment paper or silicone liners.

Step 2

Whisk together the flour, baking powder, baking soda, and salt. Set aside.

Step 3

Using an electric mixer on medium speed, beat the butter, sugar, brown sugar, and peanut butter until light and fluffy. Add the egg and vanilla, and mix well.

Step 4

Gradually add the flour mixture, mixing just until combined or a few streaks of flour remain. Stir in the peanuts.

Step 5

Drop the dough by 2-tablespoon portions onto the prepared pans. Use a fork to flatten the cookies and make a cross-hatch pattern on top of them. Bake, one pan at a time, 12-15 minutes, or until lightly browned.

Step 6

Cool the cookies on the pan on a wire rack for 5 minutes. Then transfer the cookies to a wire rack to cool completely.