Preheat your oven to 350°F (175°C). Grease an 8×8-inch baking pan and line it with parchment paper, leaving a slight overhang on the sides for easy removal later.
In a large mixing bowl, combine the melted butter, brown sugar, and granulated sugar. Whisk vigorously until the mixture is smooth and well combined.
Add the eggs one at a time, whisking well after each addition. Stir in the vanilla extract until the mixture looks glossy.
Gently fold in the all-purpose flour and salt using a spatula. Mix until just combined; be careful not to overmix, as this can make the blondies tough.
Fold in the white chocolate chips, dried cranberries, and half of the festive sprinkles. Ensure they are evenly distributed throughout the thick batter.
Spread the batter evenly into the prepared baking pan. Smooth the top with a spatula and scatter the remaining sprinkles over the surface. Bake for 25 to 30 minutes, or until the edges are golden and a toothpick inserted into the center comes out with just a few moist crumbs.
Remove the pan from the oven and let it cool completely on a wire rack. Once cooled, use the parchment paper to lift the blondies out and slice them into 16 squares.