Preheat your oven to 350°F (175°C) and line your 9x13-inch baking pan with parchment paper or lightly grease it.
In a large bowl, whisk together the melted butter and granulated sugar until well combined.
Beat in the 4 eggs, one at a time, ensuring each is fully incorporated before adding the next.
Stir in 1 teaspoon vanilla extract.
In a separate bowl, sift together the all-purpose flour, unsweetened cocoa powder, and salt.
Gradually fold the dry ingredients into the wet mixture until just combined. Be careful not to overmix.
Gently fold in the fresh or frozen cranberries, distributing them evenly throughout the brownie batter.
In another bowl, beat the softened cream cheese with powdered sugar until smooth and creamy.
Add the remaining egg and 1 teaspoon vanilla extract to the cream cheese mixture, beating until silky and fully incorporated.
Pour half of the brownie batter into the prepared baking pan, spreading it evenly.
Carefully dollop the cheesecake mixture over the brownie base, then spread it out in an even layer without mixing it into the brownies.
Spoon the remaining brownie batter on top, gently spreading to cover the cheesecake layer.
Bake the bars for 40-45 minutes, or until the edges are set but the center still has a slight jiggle.
Remove from the oven and let cool completely in the pan on a cooling rack.
Once cooled, refrigerate for at least 2 hours before slicing into bars.