Line an 8-inch square baking pan with foil or baking paper, leaving enough overhang on the sides to easily pull the fudge out once it is set. Set aside.
Combine the condensed milk and white chocolate in a medium saucepan over medium heat. Stir constantly, until the white chocolate has melted completely and the mixture is smooth. It may be quite thick.
Remove from the heat and stir in the vanilla.
Stir in the cranberries and pistachios until evenly combined.
Pour into the prepared dish and smooth the surface.
Refrigerate for at least 4 hours until set.
Once set, cut into small squares. If it is too hard to cut, leave at a room temperature for 30 minutes.
Nutritional information is an estimate and provided as a courtesy. The values may vary according to the ingredients and tools that are used. Please use your preferred nutritional calculator for more detailed information.