Cut a slit in each date and remove the pit.
Fill each date with peanut butter (about 1 teaspoon). Set aside.
Place the dark chocolate and the coconut oil in a microwave-safe bowl and melt in the microwave in 20 seconds intervals, stirring between each until smooth and melted.
Using a toothpick, dip each date into melted chocolate and coat the date until completely covered. Place the chocolate-covered dates on a tray lined with parchment paper.
Sprinkle with chopped peanuts on top of each date.
Place the dates in the fridge to allow the chocolate to firm 1 to 2 hours.