Triple-Layer Oreo Brookie Bars: Cookie, Oreo & Brownie Step-by-step instructions

Before you start

Before starting, heat the oven to 350°F (175°C) and line a 9x9-inch baking pan with parchment paper, leaving overhang on two opposite sides for easy lifting. Measure out the cookie dough and let it sit at room temperature for about 10 minutes if it is too firm to press easily.

Prepare the brownie batter according to the package or recipe instructions, but do not bake it yet. Have the Oreos ready. Gather all equipment: a mixing bowl, spatula, measuring cups, and a cooling rack. It is also helpful to have a sharp knife for slicing later.

Instructions

Build the Layers

1. 1Press the Cookie Dough Base
   Heat the oven to 350°F (175°C). Line a 9x9-inch baking pan with parchment paper, leaving overhang on two sides. Press the chocolate chip cookie dough evenly into the bottom of the pan, smoothing it into an even layer.
   Look for The dough should cover the entire bottom of the pan in a smooth, even layer.
   Tip Wet fingers slightly to press the dough without sticking.
2. 2Arrange the Oreos
   Place the Double Stuf Oreos over the cookie dough in a grid pattern, spacing them evenly. Press each cookie gently into the dough so they sit flat and stay in place when the batter is poured.
   Look for Oreos should be evenly spaced, covering the dough in a neat grid.
   Tip If using a larger pan, adjust the number of Oreos to cover the surface.
3. 3Pour the Brownie Batter
   Pour the dark chocolate brownie batter over the Oreos, spreading it gently to cover them completely. Use a spatula to level the surface, but do not stir the layers together.
   Look for The batter should fully cover the Oreos, hiding them from view.
   Tip Pour slowly to avoid moving the Oreos out of place.

At the end of this phase, the pan holds three distinct layers: a pressed cookie dough base, a grid of Oreos, and a smooth brownie batter top. The Oreos should be fully covered by the batter, and the surface should be level. The cookie dough should be evenly thick, and the Oreos should not be overlapping. The batter should be glossy and thick enough to hold its shape when spread. This is the moment to check that everything is evenly distributed and that the pan is not overfilled.

Bake to a Crinkle Crust

4. 4Bake Until Crackly
   Bake the bars at 350°F (175°C) for 30 minutes, until the top is shiny and forms a crinkle crust. The edges will be set and the center will look just barely moist. A toothpick inserted into the brownie layer (not through an Oreo) should come out with a few moist crumbs.
   Look for The top has a glossy, crackled crust and the edges pull away slightly from the pan.
   Safe temperature 160°F (71°C) internal temperature (egg dishes)
   Tip Do not overbake; the center should remain fudgy.
5. 5Cool in the Pan
   Transfer the pan to a cooling rack and let the bars cool completely in the pan, about 1 hour. The internal temperature of the brownie layer should reach 160°F (71°C) to ensure the eggs are fully set. Do not cut while hot.
   Look for The pan is cool enough to touch; the top is firm and the bars have pulled away slightly from the edges.
   Safe temperature 160°F (71°C) internal temperature (egg dishes)
   Tip For cleaner slices, chill the bars for 30 minutes after cooling.

After 30 minutes in the oven, the top of the bars should be shiny with a crackled, crinkle crust. The edges will be set and slightly pulled away from the pan, and the center will look just barely moist. The aroma of chocolate and cookies will fill the kitchen.

A toothpick inserted into the brownie layer should come out with a few moist crumbs, not wet batter. The internal temperature should read 160°F (71°C) in the brownie layer. Let the bars cool completely in the pan before lifting them out.

Slice and Serve

6. 6Slice and Serve
   Lift the bars out of the pan using the parchment overhang. Place on a cutting board and slice into 16 squares with a sharp knife. Serve warm or at room temperature, with each bar showing all three layers.
   Look for Each square reveals the golden cookie base, the dark Oreo layer, and the fudgy brownie top.
   Tip Wipe the knife clean between cuts for neat edges.

Once cooled, the bars are firm enough to slice cleanly. Lift them out using the parchment overhang and place on a cutting board. Each square should show the three layers: a golden cookie base, a dark Oreo middle, and a fudgy brownie top. The bars should hold their shape without crumbling. Serve warm or at room temperature. The texture should be chewy, gooey, and rich. If the bars are too soft, chill them for 30 minutes before slicing for neater edges.

Common mistakes

One common mistake is pressing the cookie dough too thinly, which can make the base dry and hard. Aim for a layer about 1/2 inch thick. Another is overmixing the brownie batter, which can incorporate too much air and make the top crack unevenly.

Do not stir the batter after pouring it over the Oreos, as that can drag the cookies into the brownie layer and ruin the distinct layers. Also, do not overbake: the bars should be fudgy in the center, not cakey. Finally, let the bars cool completely before slicing, or they will crumble. Use a sharp knife and wipe it clean between cuts.

How to tell it’s done

The bars are done when the top is shiny and forms a crinkle crust, and the edges have pulled away slightly from the pan. A toothpick inserted into the brownie layer (not through an Oreo) should come out with a few moist crumbs, not wet batter.

For food safety, the internal temperature of the brownie layer should reach 160°F (71°C) to ensure the eggs are fully set. The center may look slightly moist, but it will set as the bars cool. Overbaking will dry out the brownie, so start checking at 25 minutes and rely on visual cues.

• Egg dishes: 160°F (71°C) in the thickest part