Ingredients:

  • 1 cup unsalted butter, melted and cooled
  • 1.5 cups dark brown sugar, packed
  • 1 large egg, room temperature
  • 1 large egg yolk, room temperature
  • 1 tablespoon pure vanilla extract
  • 0.75 teaspoon fine sea salt
  • 2 cups all-purpose flour, spooned and leveled
  • 0.5 cup semi-sweet chocolate chips
  • 0.5 cup white chocolate chips

Instructions:

  1. Preheat your oven to 350°F (175°C). Line a 9x9 inch square baking pan with parchment paper, leaving an overhang on two sides to create a 'sling' for easy removal.
  2. In a large mixing bowl, whisk the 1 cup of melted unsalted butter and 1.5 cups of dark brown sugar vigorously for approximately 2 minutes until the sugar begins to dissolve into the fat.
  3. Add the room temperature egg, egg yolk, and 1 tablespoon of vanilla extract. Whisk until the mixture is smooth and glossy.
  4. Using a silicone spatula, gently fold in the 2 cups of all-purpose flour and 0.75 teaspoon of fine sea salt. Mix by hand only until no streaks of flour remain to avoid over-developing gluten.
  5. Fold in the semi-sweet and white chocolate chips. Transfer the batter to the prepared 9x9 pan and spread evenly.
  6. Bake for 25 minutes. The edges should be set and the top should be crackly, but the center should still remain slightly soft for a fudgy finish.
  7. Allow the blondies to cool completely in the pan before lifting them out by the parchment sling and slicing into 16 bars.