Preheat oven to 350 degrees F. Line a 13x9 inch baking dish with parchment paper.
Mix melted butter and brown sugar over medium speed with an electric mixer. Add in eggs, orange zest, and vanilla extract and beat until mixed well. Add in ground ginger, baking powder, salt, and flour, mixing until just blended.
Mix in white chocolate chips and Craisins.
Spread evenly into the bottom of prepared pan. Bake in preheated oven for 18-22 minutes until set and golden brown at the edges. Avoid over-baking - it will make the bars hard! Remove from oven and place pan on a wire rack to cool. Allow bars to cool entirely before topping with frosting.
To make the frosting, beat cream cheese and powdered sugar together with an electric mixer until smooth and creamy. Add orange zest and vanilla extract and mix well. Top cooled bars with frosting. Sprinkle with Craisins and drizzle white chocolate over the top with a fork.
For best results, place bars in the refrigerator for 30 minutes to an hour to help them set before cutting.