1. Line a baking tray or cookie sheet with parchment paper. Set aside.
2. Very finely chop the chocolate. Place it in a medium heatproof bowl. Set aside.
3. Heat the cream on the stove top or in the microwave, just until it begins to simmer.
4. Turn off the heat, and stir in half of the orange zest.
5. Immediately pour over the chopped chocolate. Allow to sit for 2 minutes.
6. Stir chocolate ganache with a spoon until smooth and shiny.
7. Let the bowl come to room temperature, then cover and refrigerate about 1 hour, until firm and easy to scoop.
8. Use a mini cookie scoop or a spoon to take out tablespoon sized amounts of chocolate. Roll into balls with your hands.
9. Place on the prepared tray. You may roll truffles in cocoa powder, crushed nuts, or other toppings if you wish.
10. Refrigerate until firm.
11. If desired, dip the chilled chocolate orange truffles in melted chocolate.
12. Garnish with the remaining orange zest. If coated in chocolate, allow to sit until the chocolate shell hardens.
13. Store leftovers in the refrigerator for up to two weeks.