Preheat oven to 350 degrees and line a large baking sheet with parchment paper.
With a standing mixer (or with a hand mixer), beat the unsalted butter and peanut butter together until well combined.
Add in brown sugar and granulated sugar, and beat the mixture until well combined.
Add in the egg, and mix until combined.
Next, add in vanilla extract. Mix until combined.
Lastly, add in baking soda, salt, and flour. Mix until all ingredients are combined.
Roll dough into balls about the size of 1 Tbsp.
Roll each ball in granulated sugar and place on the baking sheet, evenly spaced apart (about 2” apart).
Using a fork, gently make a criss cross pattern on each cookie.
Bake for 10-12 minutes, or until the cookies have set on top and are barely golden brown.
Allow to cool for 5 minutes on the baking sheet. Then, allow them to continue cooling on a wire rack.
Enjoy!
Store leftovers in an airtight container at room temperature.