Ingredients
1 ¼ cups {2 1/2 sticks) unsalted butter
2 ¼ cups all-purpose flour
1 ½ teaspoons baking powder
1 ½ teaspoons salt
2 cups packed light-brown sugar
1/2 cup granulated sugar
3 large eggs
2 ½ teaspoons pure vanilla extract

Directions
1. Preheat oven to 350 degrees. Grease a 9-by-13-inch baking pan. Line bottom of pan with parchment paper; grease parchment paper.
2. In a saucepan over medium heat, cook the butter until it turns golden brown; remove from heat, and let cool. Whisk together flour, baking powder, and salt in a small bowl.
3. In the bowl of an electric mixer, combine browned butter and both sugars; stir with a wooden spoon until combined.
4. Attach bowl to mixer; add eggs. Using the paddle attachment, beat on medium-high speed until light and fluffy, about 3 minutes. Add vanilla, and beat to combine. Add flour mixture until thoroughly combined.
5. Bake in preheated oven until a cake tester inserted in the center comes out clean, 35 to 40 minutes (do not overbake).
6. Transfer to a wire rack to cool completely before turning out of pan onto a cutting board. Peel off parchment paper; cut blondies into 3-inch squares.

Source:  Yes, it's another recipe from My Baking Addiction- because I'm a freakin' stalker!