Preheat oven to 350 degrees. Line a 9x13 inch baking pan with parchment paper.
In a medium saucepan, melt butter over medium heat (or melt in the microwave). Remove from heat and pour into a medium bowl. Stir in both sugars until they are mostly dissolved.
Quickly whisk in the eggs, followed by the vanilla, orange oil, orange zest and ginger. Stir in the baking powder and salt.
Stir in the flour, one cup at a time, until the batter is smooth. Fold in the cranberries and white chocolate chips. The batter will be sticky.
Spread the batter into the prepared pan and smooth the top. Bake for 17-20 minutes, or until the top is just golden. Remove from oven and cool completely.
Meanwhile, make the frosting by beating the cream cheese with an electric mixer until light and fluffy. Gradually mix in the powdered sugar. Stir in the vanilla and orange zest.
Spread the frosting over the cooled bars. Sprinkle with the chopped dried cranberries.
In a microwave safe bowl, melt the white chocolate chips at 50% power until smooth. Drizzle over the bars. Let the chocolate set before cutting into wedges and serving.