Preheat your oven to 350°F (175°C). Line the baking pan with parchment paper, leaving an overhang for easy removal later.
In a mixing bowl, cream together the granulated sugar and softened butter until light and fluffy.
Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
In a separate bowl, combine the all-purpose flour, baking powder, and salt. Gradually add this dry mixture to the wet ingredients, mixing just until combined.
Fold in the dried cranberries and orange zest until evenly distributed.
Pour the batter into the prepared baking pan, spreading it evenly. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Once baked, remove from the oven and allow to cool in the pan on a wire rack for about 10 minutes. Lift out using the parchment paper and let cool completely on the cooling rack.
For the frosting, beat the softened cream cheese and butter together until smooth. Gradually add the powdered sugar, mixing until well combined. Stir in the vanilla extract and orange zest.
Once the bars are completely cool, spread the cream cheese frosting evenly over the top.
Optional: Sprinkle additional chopped cranberries and orange zest on top for garnish.
Cut into 12 bars and serve.