Prepare Pan: Line a baking sheet with parchment paper or a silicone baking mat.
Melt Chocolate: Place white chocolate chips in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until completely melted and smooth (about 1-2 minutes total).
Spread: Pour melted chocolate onto the prepared baking sheet. Use a spatula to spread into a rectangle about 1/4 inch thick.
Add Toppings: Immediately sprinkle cranberries and chopped pistachios evenly over the melted chocolate. Gently press them into the chocolate with your fingers or the back of a spoon.
Chill: Refrigerate for 1 hour or until completely firm and set.
Break and Serve: Remove from refrigerator and break into irregular pieces. Store in an airtight container.