Slice each date open and remove the seed/pit, or use pre-pitted dates.
Transfer the hazelnut butter to a piping bag or use a spoon to fill each date with hazelnut butter. Place a whole hazelnut in the center and seal the dates shut.
Insert a toothpick into each date to aid in dipping later.
Melt the chocolate in the microwave in 30-second intervals, stirring until smooth. Mix in the finely chopped hazelnuts.
Dip each date into the melted chocolate, allowing any excess to drip off, then place them on a tray lined with parchment paper.
Chill the dates in the fridge or freezer until the chocolate sets.
Remove the toothpicks before serving.