Creating Key Lime Pie Bars – Browned Butter Blondie is simple by following these clear steps:

1. Preheat your Oven: Preheat the oven to 350°F (175°C). Grease a 9×13-inch baking pan or line it with parchment paper for easy removal.

2. Brown the Butter: In a saucepan over medium heat, melt the unsalted butter. Continue to cook the butter, stirring frequently, until it turns a golden brown color and emits a nutty aroma. Be careful not to let it burn. Remove from heat and let it cool slightly.

3. Mix Sugar and Eggs: In a mixing bowl, combine the brown sugar and browned butter. Whisk together until smooth. Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

4. Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking powder, and salt.

5. Combine Mixtures: Gradually add the dry ingredients to the wet mixture. Stir until just combined. Do not overmix.

6. Add Lime Zest: Fold in the lime zest until evenly distributed throughout the batter.

7. Spread Batter in the Pan: Pour and spread the blondie batter into the prepared baking pan, smoothing the top evenly.

8. 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.

9. Prepare the Key Lime Topping: In a separate bowl, whisk together the sweetened condensed milk and key lime juice until smooth.

10. Add Topping: Once the blondies are done baking, remove them from the oven and immediately pour the key lime topping over the hot blondies.

11. Return to Oven: Place the pan back in the oven and bake for another 10-15 minutes, or until the topping is set but still slightly jiggly.

12. Cool Completely: Remove the pan from the oven and allow it to cool completely at room temperature. Once cooled, refrigerate for at least 1 hour to set.

13. Slice and Dust: Once chilled, lift the bars from the pan using parchment paper and slice into squares. Dust with powdered sugar if desired.