Heat oven to 350°F. Line a 9x13-inch pan with parchment and lightly grease.
Whisk melted butter, brown sugar, and granulated sugar in a large bowl until glossy.
Whisk in the beaten eggs, vanilla, orange zest, and orange juice until smooth.
Combine flour, baking powder, and salt in a separate bowl.
Stir dry ingredients into the wet mixture just until no flour streaks remain.
Fold in cranberries and white chocolate chips to evenly distribute.
Spread batter into the pan and smooth the top with a spatula.
Bake 24–28 minutes, until golden at the edges and a tester comes out with moist crumbs.
Cool completely in the pan, then lift out, slice into bars, and serve.