Place the chopped chocolate into a medium-sized, heat-proof bowl.
In a small saucepan, heat the cream until it just begins to simmer and then pour it over the chopped chocolate. Let it sit a minute, then gently stir with a wooden spoon until the chocolate has fully melted and the ganache is smooth. Then cover and chill completely to set.
Once the filling is ready to use, melt the remaining chocolate in a microwaveable bowl for 30 seconds at a time (stirring in between) until the chocolate is smooth and fluid.
If you plan to roll the truffles, roll them into small balls using the palms of your hands and then dip into the chocolate and place on parchment paper and put in the fridge to harden.
If making cups using a chocolate mold:
Using a 1/2 teaspoon measuring spoon, drop it into mini paper cupcake liners spread evenly using a paintbrush.
Allow them to harden in the refrigerator for about 10 minutes.
Fill the chocolate covered cups with the cooled filling then brush the rest of the chocolate over the tops of the cups, sprinkle with the hazelnuts and place in the refrigerator to set again (about 15 minutes).