Preheat the oven to 350F and line two large baking sheets with parchment paper. 

Add the softened butter and light brown sugar to the bowl of a stand mixer fitted with the paddle attachment. Beat on medium speed until light and fluffy– about 1 minute. 

Next add the peanut butter, egg, and vanilla. Mix to combine and scrape down the sides of the bowl as needed. 

In a small bowl, mix together the flour, baking soda, and kosher salt. 

Add the dry ingredients to the butter mixture and mix on low speed, just until the dry ingredients are fully incorporated. 

Scoop out 1 tablespoon sized portions and place them at least 2 inches apart on the prepared baking sheet. 

(Optional) For that classic “peanut butter cookie” shape, roll the dough into smooth balls and then roll them in granulated sugar. Place them on the baking sheet and use a fork to gently press them down into a disc. 

Bake for 10-12 minutes or just until the cookies begin to brown around the edges. We want these cookies to be chewy so make sure not to overbake them! 

Allow the cookies to set completely on the tray before transferring them to airtight storage. These cookies will keep at room temperature for up to five days.