Using a hand mixer, cream together butter and sugars. Add egg and vanilla. Mix until combined.

Next, add peanut butter. Mix until well combined. Add the dry ingredients, and beat on low speed just until no flour streaks remain. Use a wooden spoon to fold in the chocolate chips.

Cover the dough, and transfer to the refrigerator to chill for at least 30 minutes. 

When you're ready to bake, preheat oven to 350 degrees. Prepare a cookie sheet with cooking spray or line with a silicone mat.

Scoop dough out of bowl and roll into balls. About 2 tablespoons of dough for each ball. Place dough on the cookie sheet 2 inches apart, and bake for 13 to 15 minutes just until the edges are lightly brown and the centers are soft.

Remove the cookies from the oven and place on cooling rack. Enjoy!

Store in an airtight container for up to 3 days.