First Step: Prepare Your Baking Pan and Oven
Preheat the oven to 325°F (162°C), or follow the temperature instructions on your boxed brownie mix, typically within 325-350°F. Grease an 8×8 or 9×9-inch baking pan thoroughly. For easier removal, consider lining the pan with parchment paper or foil, letting it hang over the sides.

Second Step: Make the Brownie Batter
If using a boxed mix, combine 18 ounces of brownie mix with 1/4 cup water, 1/3 cup vegetable oil, and 1 large egg (or a 1/4 cup pumpkin puree substitution). Fold in 1/2 cup semisweet chocolate chips for added richness. For scratch brownies, melt 1/2 cup butter with 4 ounces chopped dark chocolate; whisk in 1 cup sugar, 2 eggs, and 2 teaspoons vanilla extract. In a separate bowl, blend 1/2 cup flour, 1/3 cup cocoa powder, 1/4 teaspoon salt, and 1/4 teaspoon baking powder, then combine with wet ingredients. Set aside the batter.

Third Step: Prepare the Pumpkin Pie Layer
In a mixing bowl, blend 7.5 to 8 ounces of pumpkin puree with 6 ounces of room-temperature cream cheese until smooth. Add 3 tablespoons granulated sugar (or up to 4 tablespoons if you prefer less tang), 1 tablespoon pumpkin pie spice, and 1 large egg. Stir in 1 teaspoon vanilla extract if using. Optionally, mix in 1 tablespoon cornstarch for a firmer texture.

Fourth Step: Layer the Brownie and Pumpkin Mixtures
Pour half of the brownie batter evenly into the prepared pan. Gently spread the pumpkin mixture in an even layer over the brownie base. Cover with the remaining brownie batter and smooth the top carefully. For a marbled effect, drop dollops of the pumpkin mixture on top of the brownie batter and swirl lightly with a skewer.

Fifth Step: Bake the Pumpkin Pie Brownies
Place the pan in the oven and bake for approximately 45 to 50 minutes. This is longer than usual brownie baking times due to the thick pumpkin layer. Begin checking doneness at 45 minutes by inserting a toothpick or skewer in the center. It should come out clean or with moist crumbs, but no wet batter. The pumpkin layer should be set but may have a slight wobble.

Sixth Step: Cool and Set the Brownies
Remove the pan from the oven and allow the pumpkin pie brownies to cool completely at room temperature. For best slicing results, refrigerate the brownies for 2–4 hours or overnight. This chilling step helps the pumpkin layer fully set and makes cutting cleaner.

Final Step: Slice and Serve
Using a sharp knife, cut the cooled brownies into about 12 squares. Wipe the knife between cuts for neat edges. Serve as is or with accompaniments like whipped cream or ice cream. Store leftovers properly in an airtight container.