Start by placing the chopped dark chocolate in a heatproof bowl. In a small saucepan, heat the heavy whipping cream over medium heat until it just begins to simmer. Remove it from the heat and pour the hot cream over the chopped chocolate. Let it sit for a minute to soften the chocolate.
Using a whisk or spatula, gently stir the chocolate and cream together until smooth and glossy. Be careful not to overmix, as this can introduce air bubbles. Add the freshly grated orange zest and fold it in until evenly distributed throughout the ganache.
Cover the bowl with plastic wrap and refrigerate the ganache for about 1 to 2 hours, or until it is firm enough to scoop. The time may vary based on your refrigerator's temperature.
Once the ganache is firm, use a cookie scoop or melon baller to portion out the mixture. Roll each portion between your palms to form a smooth ball. It’s best to work quickly to prevent the ganache from becoming too soft.
If you wish, roll the truffles in cocoa powder, chopped nuts, or shredded coconut to add an extra layer of flavor and texture. Place each coated truffle on a piece of wax or parchment paper.
Transfer the truffles back to the refrigerator for another 30 minutes to firm up before serving.
