Preheat the oven to 350°F. Line a baking sheet with parchment paper.
In a medium bowl, cream the butter, peanut butter, granulated sugar, and brown sugar until light and fluffy. Beat in the egg and vanilla extract.
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt. Add the dry ingredients to the wet ingredients and mix until just combined.
Roll the dough into 1-inch balls and place them on the prepared baking sheet. Flatten the balls slightly with the palm of your hand.
Bake for 10-12 minutes, or until the edges are golden brown. Allow the cookies to cool for a few minutes before transferring them to a wire rack to cool completely.
Interesting Facts
Twinlow is a type of peanut butter cookie that is popular in the United States.
These cookies are named after the town of Twinlow, Idaho, where they originated.
Peanut butter is a great source of protein, containing 8 grams of protein per 2-tablespoon serving.