Creating these Key Lime Pie Bars – Browned Butter Blondie is an exciting and straightforward process. Follow these steps to achieve delicious results:

1. Preheat the Oven: Set your oven to 350°F (175°C) and prepare a 9×9-inch baking pan by greasing it or lining it with parchment paper.

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

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

4. Add Eggs and Vanilla: Add the eggs one at a time, mixing well after each addition. Then stir in the vanilla extract until fully incorporated.

5. Combine Dry Ingredients: In another bowl, whisk together the flour, baking powder, and salt. Gradually fold the dry ingredients into the wet mixture until just combined.

6. Press into the Pan: Pour the blondie batter into the prepared pan. Use a spatula to evenly spread and press it down.

7. Bake: Place the pan in the preheated oven and bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.

8. Prepare Key Lime Layer: While the blondies are baking, in a separate bowl, mix the sweetened condensed milk, fresh key lime juice, and lime zest. Stir until combined.

9. Add Key Lime Layer: Remove the blondies from the oven and immediately pour the key lime mixture over the hot blondie base, spreading it evenly.

10. Bake Again: Return the pan to the oven and bake for an additional 10-15 minutes, until set.

11. Cool Completely: Allow the bars to cool in the pan for at least 20-30 minutes before transferring them to a wire rack. Let them cool completely before slicing.

12. Dust with Powdered Sugar: For a finishing touch, sprinkle powdered sugar on top before serving.