Cream the butter and the sugar with an electric mixer until nicely combined and fluffy.
Grate the chocolate and combine it with the rolled oats, cocoa powder, coffee and raspberries. Stir and add to the butter mixture.
Start the mixer again at low speed and mix until combined. Set the mixer aside and roll the chocolate balls between the palm of your hands. This amount should yield 8 balls weighing between 35-40 g each.
Melt the remaining chocolate on a double boiler or in the microwave and let sit until it's cool enough to handle. Spread the chocolate over each ball gently coating all the surface. Place each ball on a piece of parchment paper. Sprinkle some freeze-dried raspberries on the top before the chocolate hardens.
This recipe can be easily doubled if catering for a larger party. Chocolate balls are an excellent gift for the holiday season as they can be stored in the fridge for a couple of weeks.