Creating Key Lime Pie Bars – Browned Butter Blondie is a breeze when you follow these straightforward steps:

1. Preheat your oven: Set it to 350°F (175°C) and line a 9×13 inch baking pan with parchment paper, leaving an overhang for easy lifting.

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

3. Mix the Blondie Base: In a large bowl, combine the browned butter and brown sugar. Beat well until smooth. Add in the eggs, one at a time, followed by the vanilla extract.

4. Combine Dry Ingredients: In another bowl, whisk together the flour, baking powder, and salt. Gradually add this mixture to the wet ingredients, mixing just until combined.

5. Spread the Blondie Batter: Evenly spread the blondie batter into the prepared baking pan.

6. Prepare the Key Lime Filling: In a mixing bowl, whisk together the sweetened condensed milk, key lime juice, egg yolks, and lime zest until smooth.

7. Pour Filling: Carefully pour the key lime mixture over the blondie batter, ensuring even distribution.

8. Bake: Place the pan in the preheated oven and bake for 30-35 minutes, or until the filling is set and a toothpick inserted in the blondie comes out clean.

9. Cool Down: Remove the pan from the oven. Let it cool for about 15-20 minutes at room temperature, then refrigerate for at least an hour to firm up before cutting.

10. Cut and Serve: Lift the bars out of the pan using the parchment overhang. Cut into squares or rectangles and serve chilled.