Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.
In a large bowl, whisk together the flour, granulated sugar, brown sugar, baking soda, and salt.
Add the melted butter, egg, and vanilla extract. Mix until just combined. Stir in the cranberries, white chocolate chips, and orange zest.
Pour the batter into the prepared pan and spread evenly. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Let the bars cool completely in the pan before frosting.
For the frosting: In a medium bowl, beat together the cream cheese and butter until smooth. Gradually add the powdered sugar and mix until well combined. Stir in the orange zest and vanilla extract.
Spread the frosting evenly over the cooled bars. Cut into squares and serve.
Notes
Store leftover bars in an airtight container in the refrigerator.