• 12 tablespoons butter, melted and cooled, plus more for the pan
  • 1 1/2 cups all-purpose flour
  • 1 1/2 cups packed dark brown sugar
  • 1 cup plus 2 tablespoons bittersweet chocolate chips
  • 2 large eggs, lightly beaten
  • 1/2 cup toasted walnuts, coarsely chopped
  • 1 tablespoon vanilla extract
  • 1 teaspoon baking powder
  • 1/2 teaspoon kosher salt


  1. Preheat the oven to 350° F. Butter a 9×13 inch baking pan. Line the pan with parchment, leaving an overhang, then butter the parchment.
  2. Whisk the flour, baking powder and salt together in a medium bowl and set aside. In another bowl, whisk the melted butter and brown sugar together until combined.
  3. Add the vanilla and eggs and stir to combine. Fold the flour mixture into the wet ingredients, being careful not to overmix.
  4. Fold in the walnuts and 1 cup of the chocolate chips. Pour the batter into the prepared pan and smooth the top. Scatter the remaining 2 tablespoons chocolate chips over the batter.
  5. Bake until the top is a light golden brown, 20 to 25 minutes, being careful not to overbake. Let cool on a wire rack.