Combine the chopped white chocolate and sweetened condensed milk in a microwave safe or heat-proof bowl.
Microwave method: Microwave stirring every 20 seconds to distribute heat, until the white chocolate is melted.
Stove-top method: Place a small pot, smaller than the heat-proof bowl, half filled with water on the stove-top over medium heat. Carefully set the bowl of white chocolate and condensed milk on top of the pot. Bring the water to a simmer, and let the chocolate melt slowly, stirring occasionally. The double boiler method takes longer than the microwave, but there’s almost zero risk of scorching the chocolate, so I prefer this method.
When the white chocolate is melted, stir to combine well. Remove the bowl from the heat.
Stir the dried cranberries into the mixture until evenly distributed.
Pour the mixture into a parchment lined 8x8-inch square pan. Use an offset spatula to smooth out the top.
Refrigerate the white chocolate fudge until set, about 2 hours.
Remove from the refrigerator and use the parchment paper to remove the fudge from the baking pan. Cut it into 1.5-inch squares. Refrigerate until ready to serve