Preheat your oven to 350°F. While it heats, grease a 9x13 inch baking dish thoroughly with butter or non-stick spray, making sure to coat the bottom and all sides evenly. This prevents sticking and helps the brownies bake uniformly.

Cut the butter into smaller chunks and place in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until completely melted (this usually takes 1-1.5 minutes total). Add the brown sugar to the melted butter and stir vigorously until well combined and smooth. The mixture should look like wet sand with no visible butter streaks.

Let the butter-sugar mixture cool for about 5 minutes until it's warm but no longer steaming—this prevents the eggs from scrambling. Add the room temperature eggs one at a time, stirring well after each addition to create an emulsified batter. The mixture should look glossy and thick. Stir in the red velvet emulsion and vanilla extract until the color is evenly distributed throughout. I find that room temperature eggs incorporate much more smoothly into the batter, creating a better texture in the final brownie.

In a separate bowl, whisk together the cocoa powder, salt, and flour until no lumps remain—this distributes the ingredients evenly and prevents streaks of cocoa in the final brownies. Pour the wet mixture from Step 3 into the dry ingredients and stir until just combined, being careful not to overmix. Fold in the 16 roughly chopped Oreo pieces gently, distributing them throughout the batter.

Pour the batter into the prepared pan from Step 1, using a spatula to spread it evenly into the corners. Crush the remaining 4 Oreo cookies into rough 1/4-inch pieces and sprinkle them evenly over the top of the batter. I like to press them down slightly so they set into the brownie as it bakes, creating pockets of cookie throughout.

Place the pan in the preheated 350°F oven and bake for 55 to 65 minutes, until a toothpick inserted into the center comes out with just a few moist crumbs (not wet batter). The brownies should look slightly set on top but still have a slight jiggle in the very center. Remove from the oven and let cool in the pan for 15 to 20 minutes—this allows the structure to set properly without the brownies becoming too firm. Once cooled, cut into squares and serve.