In a large mixing bowl, add the peanut butter and brown sugar and mix until combined. Fold through the chocolate chips. Cover the bowl and freeze for an hour.
Preheat the oven to 180C/350F. Line a large baking sheet with parchment paper.
Remove the mixing bowl from the freezer. Using your hands, form 12 balls of dough and place them onto the lined sheet. Bake the cookies for 15-20 minutes, or until they are firm around the edges.
Remove the cookies from the oven and let them cool completely.
TO STORE: Place cookies onto a plate and cover them in plastic or saran wrap, and keep them at room temperature for up to 5 days. You can also store them in the refrigerator and they will keep for up to 2 weeks. TO FREEZE: Leftover cookies can be stored in the freezer in a sealable container. The cookies will keep well for up to 6 months.