Preheat oven to 350 degrees. Line a 10 X 15 baking sheet with parchment paper, letting the edges extend past the rim by about 2 inches.
In a medium bowl, whisk together 2 3/4 cups flour, 1 teaspoon salt, 1/8 teaspoon baking soda, and 1/2 teaspoon baking powder. Set aside.
In a large bowl of a stand mixer fitted with the paddle attachment, beat 1. cup butter and 8 ounces of cream cheese on medium speed until well blended and fluffy, about 3 minutes. Add 1 1/4 cups granulated sugar and beat until smooth, about 2 minutes.
Add 1 egg and 1 tablespoon vanilla and beat on low speed until well combined, scraping down the bowl with a rubber spatula as necessary.
Reduce mix speed to low and gradually add the flour mixture. Mix just until blended.
Stir in 2 cups white chocolate chips and 1 3/4 cups cranberries.
Using a spatula, transfer the dough onto the prepared baking pan and spread it into an even layer. If dough is too sticky, lightly moisten fingers with water and pat down into an even layer.
Bake in 350 degree oven just until the edges are starting to turn light golden brown, and a toothpick inserted in the middle has moist crumbs, about 25 minutes. (Do not overbake! The bars should be quite moist, and almost slightly underbaked in the middle.)
Remove the pan from the oven and set it on a wire rack. Let cool completely. When fully cooled, remove the bars from the pan using the overhanging parchment paper and slice into bars.