Preheat your oven to 350°F and line baking sheets with parchment paper. Set them aside for now.

In a large bowl, cream together the softened butter and light brown sugar until smooth. Next, beat in the egg, vanilla extract, and creamy peanut butter until fully combined.

Gradually add in the all-purpose flour and baking soda. Mix until just incorporated, being careful not to over-mix the dough.

Scoop out 1-2 tablespoons of dough and roll into balls. If you like, roll the dough balls in granulated sugar. Place them about an inch apart on the prepared baking sheet, as they won't spread much.

Optionally, use a fork to press down on the dough balls in both directions, creating a criss-cross pattern.

Bake the cookies for 7-8 minutes. Let them cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.