1. Line a baking sheet with parchment paper and finely chop the white chocolate; place it in a heatproof bowl.

2. In a small saucepan, gently heat the heavy cream, unsalted butter, and half of the orange zest until steaming but not boiling, stirring to melt the butter.

3. Remove from the heat, stir in the remaining orange zest, orange juice, vanilla, optional orange liqueur, and sea salt, then pour the hot mixture over the white chocolate and let sit for 2–3 minutes.

4. Whisk the mixture from the center outward until the chocolate is completely melted and the ganache is smooth and glossy.

5. Press plastic wrap directly onto the surface of the ganache and refrigerate for 1–2 hours, until firm enough to scoop but still pliable.

6. Scoop teaspoons of ganache onto the lined baking sheet and roll each portion between your palms to form smooth balls; chill again for 15–20 minutes.

7. Melt the dark chocolate in a heatproof bowl over a pan of barely simmering water or in short microwave bursts, stirring until smooth.

8. Place the chocolate sprinkles in a shallow bowl, dip each chilled ganache ball into the melted dark chocolate, let the excess drip off, then roll in sprinkles to coat.

9. Return the finished truffles to the baking sheet and refrigerate for 20–30 minutes, or until the coating is fully set.

10. Store the truffles in an airtight container in the refrigerator until ready to serve.