Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking dish, or line it with parchment paper for easy removal.

In a saucepan over medium heat, melt the butter until it turns a golden brown color and has a nutty aroma, stirring frequently. Remove from heat and let it cool slightly.

In a mixing bowl, combine the browned butter with the brown sugar and granulated sugar, whisking until smooth.

Add the eggs and vanilla extract to the mixture, whisking until fully incorporated.

In another bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Pour half of the batter into the prepared baking dish, spreading it evenly over the bottom.

In a saucepan, combine the cranberries, orange juice, and orange zest. Cook over medium heat until the cranberries start to burst and the mixture thickens (about 10 minutes). Remove from heat.

Spread the cranberry mixture evenly over the batter in the baking dish.

Drop spoonfuls of the remaining batter over the cranberry layer, leaving some of the filling visible.

Bake in the preheated oven for 30-35 minutes or until the top is set and lightly golden.

Allow the bars to cool in the pan on a cooling rack for about 30 minutes before cutting into squares.

To make the glaze, whisk powdered sugar with milk until smooth, then drizzle over cooled bars.