01 -
Preheat the oven to 350°F (175°C) and line an 8 by 8-inch pan with aluminum foil or parchment paper.
02 -
Melt 6 tablespoons of butter in a small saucepan over medium heat. Swirl the pan occasionally as it becomes foamy and produces cracking noises. When the crackling stops, continue swirling until the butter develops a nutty aroma and amber-colored bits form at the bottom, about 2-3 minutes. Remove from heat and pour into a mixing bowl. Stir in the remaining 2 tablespoons of butter until melted.
03 -
Combine the browned butter with dark brown sugar and stir until smooth. Let the mixture cool slightly. Add the egg, egg yolk, and vanilla extract, stirring until smooth.
04 -
Stir in the salt and flour until fully combined. Mix in the milk chocolate chips, white chocolate chips, and semisweet chocolate chips.
05 -
Pour the batter into the prepared pan. Sprinkle additional chocolate chips on top and press lightly into the batter.
06 -
Bake for approximately 25 minutes or until the edges are golden. Let the blondies cool on a rack before cutting into squares.
07 -
Store blondies in an airtight container at room temperature for up to 1 week, or freeze for up to 3 months.