Finely chop the dark chocolate and grate the fresh orange zest, setting both aside. Line a baking tray with parchment paper and place the chocolate sprinkles into a shallow bowl.

In a small saucepan, combine the cold heavy cream with the grated orange zest. Heat the mixture over medium heat until it reaches a gentle simmer around the edges. Do not allow it to boil vigorously. Remove the saucepan from the heat as soon as small bubbles begin to appear.

Immediately add the chopped dark chocolate to the hot cream mixture. Allow the chocolate to rest undisturbed for 2–3 minutes. After resting, gently stir from the center outward using a spatula or whisk until a smooth and cohesive ganache forms. Ensure the mixture is fully melted and free of lumps.

Transfer the ganache to a shallow dish or small baking pan to promote even cooling. Refrigerate for a minimum of 2 hours, or until the ganache is firm yet pliable enough to be shaped without excessive softness.

Once firm, use a small spoon or mini scoop to portion the ganache into small amounts. Roll each portion between your palms to form uniform spheres. Immediately place each truffle into the bowl of chocolate sprinkles, coating all sides thoroughly. Gently press the sprinkles onto the truffles to ensure proper adherence.

Arrange the coated truffles on the prepared parchment-lined tray. Refrigerate for an additional 30 minutes to allow the truffles to set completely. After chilling, transfer the truffles to an airtight container and store them in the refrigerator until ready to serve.