Add the coconut oil, cacao powder, and sweetener to a small saucepan placed over medium-low heat.

Once the mixture is barely melted, remove it from the heat and stir in nut butter.

Line a mini-muffin tray with paper liners. Pour the peanut butter cup mixture into the cups, filling them ¾ the way full. Freeze for 15-20 minutes or until hardened. Once frozen, remove from tin and place in freezer bags. Store in the freezer. Enjoy!