Preheat your oven to 350°F (160°C) and line a baking sheet with parchment paper.
In a large bowl, mix together the peanut butter, brown sugar, and egg until well combined.
Scoop out tablespoon-sized portions of dough and place them onto the lined baking sheet, spacing them about 2 inches apart. This recipe should make around 15 cookies.
Bake for 10-12 minutes, or until the edges are golden brown.
Let the cookies cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.