Ingredients
For the pumpkin mixture:
  • 1 cup all-purpose flour
  • ½ teaspoon baking powder
  • ½ teaspoon salt
  • ⅔ cup sugar
  • 2 large eggs
  • 1 teaspoon vanilla extract
  • 1 cup pumpkin puree
  • ¼ cup vegetable oil
  • 1 teaspoon ground cinnamon
  • ¼ teaspoon ground nutmeg
For the chocolate mixture:
  • 9 tablespoons unsalted or salted butter, cut into pieces
  • 12 ounces bittersweet or semisweet chocolate, chopped
  • 1 cup, plus 2 tablespoons sugar
  • 1½ teaspoon vanilla extract
  • 3 large eggs, at room temperature
  • ⅓ cup all-purpose flour
  • 1½ cups pecans, toasted and coarsely chopped
Instructions
  1. Preheat the oven to 350°F. Line the inside of a 10×10-inch or 13×9-inch baking pan with parchment paper.
  2. Start by making the pumpkin mixture. In a medium bowl, whisk together the flour, baking powder, and salt. Set aside. In a large bowl, beat together the sugar, eggs, vanilla, pumpkin puree, oil, cinnamon, and nutmeg until well-combined. Gently fold in the flour mixture until just combined.
  3. Then make the chocolate brownie mixture. In a medium saucepan over medium low heat, melt 9 tablespoons of butter. Add the chocolate and stir over low heat until the chocolate is melted and smooth. Turn the heat off, and immediately stir in the sugar and vanilla until combined. Beat in the eggs one at a time. Add the flour and stir energetically for 1 full minute, until the batter loses its graininess, becomes smooth and glossy, and pulls away a bit from the sides of the saucepan. Stir in the chopped nuts.
  4. Transfer half of chocolate batter to prepared pan, smoothing the top with a rubber spatula. Top with ⅔ of pumpkin batter. Add the other half of the chocolate layer, and spread to the edges. Using a spoon, spread out the remaining pumpkin batter in 4 stripes across the pan. Use a butter knife to swipe across the stripes of pumpkin batter (the knife should be perpendicular to the stripes).
  5. Bake until set, 50-55 minutes. Cool in the pan before lifting out of the pan and cutting into squares. The brownies taste better when completely cooled and set for a few hours, so make them in the morning and eat them in the evening while you’re welcoming trick-or-treaters!