- 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
- 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.
- 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.
- Add the vanilla and eggs and stir to combine. Fold the flour mixture into the wet ingredients, being careful not to overmix.
- 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.
- Bake until the top is a light golden brown, 20 to 25 minutes, being careful not to overbake. Let cool on a wire rack.