Ingredients:

  • 1/2 cup (1 stick) unsalted butter, melted
  • 1 1/2 cups dark brown sugar, packed
  • 2 large eggs (room temperature preferred)
  • 1 teaspoon vanilla extract
  • 1 1/2 cups all-purpose flour (spooned and leveled)
  • 1 teaspoon baking powder
  • 1/2 teaspoon kosher salt
  • For Glaze (Optional): 2 tablespoons unsalted butter
  • For Glaze (Optional): 1/4 cup dark brown sugar
  • For Glaze (Optional): 1 tablespoon milk or cream
  • For Glaze (Optional): 1 cup powdered sugar, sifted

Instructions:

  1. Preheat the oven to 350°F (175°C). Line a 9x13 inch metal baking pan with parchment paper, leaving an overhang on the two long sides. Lightly grease any exposed pan sides.
  2. In a large mixing bowl, whisk the melted butter and packed dark brown sugar until the mixture becomes glossy and uniform.
  3. Incorporate the eggs one at a time, whisking vigorously for 30 seconds after each addition. Stir in the vanilla extract.
  4. Whisk together the flour, baking powder, and salt in a separate small bowl. Gradually add the dry mixture to the wet mixture, folding gently with a rubber spatula until just combined. Do not overmix.
  5. Transfer the batter to the prepared pan, spreading it into an even layer. Bake for 25–30 minutes. The edges should look golden brown, but the center should still look slightly soft.
  6. Remove from the oven and allow the bars to cool completely in the pan for at least 60 minutes for maximum chewiness.
  7. If making the glaze: In a small saucepan, melt the butter and brown sugar over medium heat, stirring until smooth. Remove from heat, stir in the milk, then whisk in the sifted powdered sugar until smooth.
  8. Drizzle or spread the optional glaze evenly over the cooled bars. Once the glaze is set, use the parchment overhang to lift the bars out of the pan and cut into 16 squares.