Follow these detailed steps to bake and assemble your delicious pumpkin patch. The process is straightforward and fun, perfect for getting little helpers involved in the kitchen.

1. Preparation and Preheating: First things first, preheat your oven to 350°F (175°C). Prepare a 9×13-inch baking pan by lining it with parchment paper, leaving a couple of inches of overhang on the two long sides. This overhang will act as “handles,” allowing you to easily lift the entire slab of brownies out of the pan once they’ve cooled. Lightly grease the parchment paper and the uncovered sides of the pan with baking spray or butter.
2. Combine Wet Ingredients: In a large mixing bowl, combine the melted butter, granulated sugar, and packed light brown sugar. Whisk them together vigorously for about a minute. The mixture should become glossy and slightly thickened. This step is crucial for dissolving the sugars and creating that signature crackly top on your brownies.
3. Incorporate Eggs and Vanilla: Add the 4 room-temperature eggs to the sugar mixture, one at a time, whisking well after each addition until it is fully incorporated. Once all the eggs are in, whisk for another minute until the batter is smooth, thick, and pale. Stir in the pure vanilla extract.
4. Add Dry Ingredients: Place a fine-mesh sieve over your bowl. Sift the Dutch-process cocoa powder, all-purpose flour, and kosher salt directly into the wet ingredients. Sifting aerates the dry ingredients and removes any lumps, which is especially important for cocoa powder. This ensures a smooth, lump-free batter.
5. Fold Gently: Using a rubber spatula, gently fold the dry ingredients into the wet ingredients. Be careful not to overmix! Fold just until you no longer see any dry streaks of flour or cocoa. Overmixing develops the gluten in the flour, which leads to tough, cakey brownies instead of dense, fudgy ones.
6. Add Chocolate Chips: Pour in the semi-sweet chocolate chips and gently fold them into the batter until they are evenly distributed.
7. Bake the Brownies: Pour the brownie batter into your prepared 9×13-inch pan and use the spatula to spread it into an even layer, making sure it reaches all the corners. Bake on the center rack of your preheated oven for 30-35 minutes.
8. Check for Doneness: The brownies are done when a wooden skewer or toothpick inserted into the center comes out with moist, fudgy crumbs attached, but not wet batter. If it comes out clean, they are likely overbaked. It’s better to slightly underbake than overbake for the fudgiest texture.
9. Cool Completely: This is the most important and perhaps the most difficult step due to the amazing smell! Remove the pan from the oven and place it on a wire cooling rack. Let the brownies cool completely in the pan, which can take at least 2-3 hours. Do not attempt to frost or cut them while they are still warm, as they will be too soft and will fall apart.
10. Prepare the “Dirt”: While the brownies are cooling, prepare your toppings. Place the Oreo cookies in a zip-top plastic bag. Seal the bag, removing most of the air, and use a rolling pin or the bottom of a heavy glass to crush the cookies into a coarse crumb mixture. You want a variety of sizes to resemble soil, not a fine powder.
11. Create the “Vines”: If your green frosting is in a tub, transfer some of it to a piping bag fitted with a small round tip (like a Wilton #3 or #4) or a zip-top bag with a tiny corner snipped off. This gives you precise control for drawing the vines.
12. Assemble the Pumpkin Patch: Once the brownies are completely cool, lift them out of the pan using the parchment paper handles and place them on a cutting board or serving platter. Sprinkle the crushed Oreo “dirt” evenly over the entire surface of the brownies.
13. Pipe and Place: Use your piping bag to pipe squiggly green lines and loops across the Oreo dirt, creating the look of pumpkin vines weaving through the patch. Finally, gently press the candy pumpkins onto the brownies, placing them along the green “vines.” Your delicious and adorable Pumpkin Patch Brownies are now ready to be admired and devoured!