Place the chocolate pieces in a heat proof bowl.

Heat the heavy cream in a saucepan and bring it to a boil, about 10 minutes.

Pour the boiling cream over the melted chocolate through a sieve and leave undisturbed for 15 minutes.

Stir gently with a whisk to combine the chocolate and cream ingredients until you have a shiny and smooth ganache. If there are any chocolate chunks remaining, melt them completely on a double boiler.

Pour the ganache into a loaf pan, cover and refrigerate until the ganache solidifies, about 1 hour.

Scoop small balls of the ganache using a melon baller and roll into 3/4-inch sized balls using cool fingertips. Roll the truffles in cocoa powder.

You can keep the truffles in the refrigerator in a sealed container, but serve them at room temperature.