Creating Key Lime Pie Bars – Browned Butter Blondie can be done in just a few easy steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking pan.

2. Brown the Butter: In a medium saucepan, melt the butter over medium heat. Continue cooking, stirring frequently, until the butter turns golden brown and smells nutty. Remove from heat and let cool slightly.

3. Mix the Sugars: In a large mixing bowl, combine the browned butter, brown sugar, and granulated sugar. Whisk until smooth.

4. Add Eggs and Vanilla: Add the eggs, one at a time, whisking well after each addition. Stir in the vanilla extract.

5. Combine Dry Ingredients: In another bowl, whisk together the flour, baking powder, baking soda, and salt.

6. Fold Mixtures Together: Gradually add the dry ingredients to the wet mixture, stirring until just combined. Do not overmix.

7. Spread the Batter: Pour the batter into the prepared baking pan, spreading it evenly to the edges.

8. Prepare the Key Lime Mixture: In a separate bowl, whisk together the sweetened condensed milk, key lime juice, and lime zest until well combined.

9. Add Key Lime Mix: Pour the key lime mixture over the blondie batter and gently spread it to cover evenly.

10. Bake: Bake in the preheated oven for 25-30 minutes or until the edges are set and a toothpick inserted in the center comes out clean. The key lime layer might still jiggle slightly, which is okay.

11. Cool: Allow the bars to cool in the pan on a wire rack for about 1 hour before slicing.

12. Slice and Serve: Once cooled, cut into squares and dust with powdered sugar if desired.