Line a baking sheet with parchment paper, set aside.

In a microwave-safe bowl, melt the semi-sweet chocolate chips using 30-second intervals, stirring in between until melted.

Pour onto the prepared baking sheet and spread evenly with the back of a spoon.

In a small microwave-safe bowl, melt the white chocolate chips in 20 second intervals, stirring in between until melted.

Drizzle over the chocolate layer. Use a toothpick or knife to swirl the layers together.

Sprinkle the top of the bark with sanding sugar.

Place in the refrigerator for about 30 minutes to harden and set. Break the bark into pieces. Store in a sealed container in the refrigerator.