1. Melt the white chocolate and butter together in a microwave-safe bowl using short intervals, stirring until smooth.

2. Stir in the eggnog, vanilla extract, nutmeg, salt, and crushed graham cracker crumbs until the mixture is creamy and fully combined.

3. Chill the mixture in the refrigerator for 1 to 2 hours, or until firm enough to scoop.

4. Scoop small portions and roll them into balls, then place them on a parchment-lined tray.

5. Freeze or chill the rolled truffles for 15 to 20 minutes so they stay firm for dipping.

6. Melt the dark chocolate with the coconut oil until smooth and glossy.

7. Dip each truffle into the melted dark chocolate, let the excess drip off, and place back on the tray.

8. Garnish with extra crumbs or a drizzle of melted white chocolate before the coating sets.

9. Chill briefly until the chocolate shell is firm, then serve or store.