Preheat your oven to 350°F. Line a 9×13” baking pan with foil and spray it with nonstick cooking spray. This ensures that your brookies come out easily once baked.
In the bowl of a stand mixer fitted with the paddle attachment, place the melted butter, pumpkin puree, brown sugar, and granulated sugar. Mix until everything is combined and creamy.
Next, add in the egg yolk and vanilla extract, continuing to mix until incorporated. This will add richness and flavor to your batter.
Now, sprinkle in the baking soda, nutmeg, cinnamon, ginger, and allspice. Blend until well mixed, scraping the sides of the bowl as necessary.
Gradually add the flour to the mixture. Keep mixing until a smooth dough forms. You want a thick consistency that holds together.
Press the dough evenly into the bottom of the prepared pan. This will form your cookie layer, so make sure it’s uniform.
If you’re using a brownie mix, prepare it as directed on the box. If you’re opting for homemade brownies, melt the baking chocolate and unsalted butter in a large, microwave-safe bowl. Heat on high for 2 to 3 minutes, stirring every 30 seconds until it’s smooth.
Next, stir in the sugar until well combined, then add in the eggs, vanilla, and cocoa powder. Mix until everything is integrated.
Carefully fold in the additional flour until just combined. You don’t want to overmix, as this can lead to tough brownies.
Pour the brownie batter over the cookie layer, spreading it evenly across. This is where the magic happens, blending two delicious layers!
Sprinkle the top with chocolate chips for an added treat!
Bake in your preheated oven for 25 to 35 minutes. You’ll know they’re done when the brownies look set, and a toothpick inserted in the center comes out with a few moist crumbs.
Once baked, allow your brookies to cool in the pan before slicing them into squares. Enjoy your Fudgy Pumpkin Brookies warm or at room temperature!