Ultimate Oreo Brookies Bars (cookies & Cream) for Parties

Fudgy brownie meets chewy cookie with crunchy cookie sandwiches, all in one pan—quick to prep, no chill, and dangerously crowd-pleasing.

You want a dessert that shuts down the room? Stack a fudgy brownie, a chewy cookie layer, and crunchy cookie-and-cream bits in one bar, then watch people “just try a bite” and come back for three. The texture play is wild: crisp edges, gooey center, and crunch where it counts. It’s the treat that feels over-the-top but comes together fast with pantry staples. No chilling, no stress, just hero-level bars in under an hour of hands-on time. And yes, they slice clean… if you can wait for them to cool.

Why This Recipe Works

• Two layers, one pan: A fudgy brownie base supports a plush cookie layer, so every bite hits chocolatey and buttery notes without collapsing.
• Smart texture engineering: Cocoa-forward brownies + cornstarch in the cookie dough = soft-chewy on top, dense-fudgy on bottom, and crisp around the edges.
• Oreos, three ways: Folded into dough, scattered between layers, and sprinkled on top for that signature cookies-and-cream crunch and flavor.
• No-chill cookie dough: Creamed butter and the right dry ratios set up in the oven—no fridge time, no waiting around. FYI, that’s how you win weeknights.
• Clean slice strategy: A parchment sling and a brief chill after cooling give bakery-style squares without smearing the layers.
• Balanced sweetness: Dark cocoa and a pinch of espresso powder deepen the chocolate, keeping the bars rich—not cloying.

Ingredients

Brownie Layer

• 10 tbsp (140 g) unsalted butter, melted and slightly cooled
• 3/4 cup (150 g) granulated sugar
• 1/2 cup (100 g) light brown sugar, packed
• 2 large eggs + 1 large yolk, room temperature
• 1 1/2 tsp pure vanilla extract
• 1/2 tsp espresso powder (optional, boosts chocolate flavor)
• 1/2 tsp fine sea salt
• 1/2 cup (60 g) unsweetened cocoa powder (Dutch-process or natural)
• 3/4 cup (95 g) all-purpose flour
• 1/2 cup (90 g) semisweet chocolate chips or chopped dark chocolate

Cookie Layer

• 1/2 cup (113 g) unsalted butter, softened
• 1/2 cup (100 g) granulated sugar
• 1/2 cup (110 g) light brown sugar, packed
• 1 large egg, room temperature
• 2 tsp pure vanilla extract
• 1 1/2 cups (190 g) all-purpose flour
• 1 tbsp (8 g) cornstarch (for extra softness)
• 1/2 tsp baking soda
• 1/2 tsp baking powder
• 1/2 tsp fine sea salt
• 3/4 cup (135 g) chocolate chips (mix of semisweet and white, if you like)

Cookies & Cream

• 16–18 Oreo-style sandwich cookies (about 180–200 g), coarsely chopped, divided

Let’s Get Cooking – Instructions

1. Prep the pan: Heat oven to 350°F (175°C). Line a 9-inch square pan with parchment, leaving overhang on two sides for a sling. Lightly grease.
2. Make the brownie base: In a large bowl, whisk melted butter, granulated sugar, and brown sugar until shiny and combined, about 30 seconds. Whisk in eggs, yolk, vanilla, espresso powder, and salt until glossy and slightly thickened, 45–60 seconds.
3. Dry into wet: Sift in cocoa powder and flour. Use a spatula to fold just until no dry streaks remain. Fold in chocolate chips. Spread the batter evenly in the prepared pan.
4. Cookie dough time: In a separate bowl, beat softened butter with granulated and brown sugars until creamy and light, 1–2 minutes. Beat in egg and vanilla until smooth.
5. Whisk and fold: In another bowl, whisk flour, cornstarch, baking soda, baking powder, and salt. Add dry ingredients to the butter mixture and mix on low until a soft dough forms. Fold in chocolate chips and about 1 cup (100 g) chopped cookies.
6. Layer it up: Scatter a handful of chopped cookies over the brownie layer. Using your hands, pinch off pieces of cookie dough and dot them all over. Lightly press to connect the pieces into an even layer. Sprinkle remaining chopped cookies on top and gently press to adhere.
7. Bake: Bake on the middle rack for 32–36 minutes, until the top is golden and set and a toothpick inserted in the center meets fudgy crumbs but no wet batter. The edges will look puffed.
8. Cool for clean slices: Let the pan cool on a rack for 1 hour. Lift out with the sling and cool 30 minutes more. For razor-sharp edges, chill 20–30 minutes before slicing.
9. Finish and serve: Cut into 16 bars (or 25 smaller bites). Optional but elite: a tiny pinch of flaky sea salt on each warm bar.

Preservation Guide

• Room temperature: Store bars in an airtight container for 3 days. Layer with parchment to keep the tops pretty.
• Refrigerator: Keep in a sealed container for 5–6 days. Bring to room temp or microwave 10–12 seconds for peak gooeyness.
• Freezer: Wrap bars individually, then place in a freezer bag for up to 3 months. Thaw at room temp 30–45 minutes or warm from frozen at 300°F (150°C) for 6–8 minutes.
• Keep the crunch: If the cookie bits soften over time, pop bars in a 300°F oven for 5–7 minutes to revive texture.

Nutritional Perks

• Cocoa benefits: Dark cocoa brings flavonoids and deep chocolate flavor, so you can use less sugar elsewhere without losing impact.
• Satisfying fats and protein: Butter and eggs increase satiety; one square actually feels like a treat, not a tease.
• Built-in portion control: Clean, sturdy bars mean you can serve small squares at events without crumbs or chaos.
• Energy treat, not a meal: These are dessert bars—delicious and rich. A reasonable portion lands around the mid-300s calories depending on cut size.

Avoid These Mistakes

• Overbaking: Pull them when a toothpick shows moist crumbs. Waiting for a dry pick = dry, cakey layers.
• Skipping the parchment sling: You’ll fight the pan and lose corner pieces. Use the sling—thank yourself later.
• Cold ingredients: Cold eggs or butter can cause a greasy or curdled dough. Room temp means smoother mixing and better texture.
• Overmixing the cookie dough: Mix just until combined after adding flour. Overmixing activates gluten and toughens the top layer.
• Packing the flour: Scoop-and-level or weigh. Too much flour turns the cookie layer dry and bready.
• Uneven layers: Dot and press cookie dough gently to cover; thick mounds can sink or underbake while edges overbake.
• Using a dark, unlined pan: Dark metal runs hot. Line and check early, or reduce bake time by 2–3 minutes.
• Ignoring cooling time: Cutting too soon smears layers. Let them set; a brief chill pays off in bakery-worthy squares.

Mix It Up

• Mint-chocolate vibe: Swap in mint sandwich cookies and add 1/2 tsp peppermint extract to the cookie dough.
• Peanut butter swirl: Warm 1/3 cup peanut butter and swirl over the brownie layer before adding cookie dough.
• Double chocolate: Use dark chocolate chunks in both layers and dust the top with cocoa before baking.
• White chocolate dream: Fold white chips into the cookie dough and top with extra for a bakery look.
• Salty finish: Sprinkle flaky sea salt on top after baking to cut sweetness and boost chocolate notes.
• Gluten-free: Replace flour 1:1 with a quality GF blend containing xanthan gum; bake time may be 2–4 minutes longer.
• Dairy-free: Use plant butter sticks and dairy-free chips; the structure holds and flavor stays bold.
• Skillet brookies: Press layers into a 10-inch oven-safe skillet and bake 25–30 minutes; serve warm with ice cream.
• Caramel core: Drizzle 1/3 cup thick caramel over the brownie layer; freeze 5 minutes before adding cookie dough to prevent sinkage.

FAQ

Can I use box mixes for the layers?

Yes. Use a boxed brownie mix for a 9-inch pan and your favorite cookie dough mix on top, then add chopped cookies. Start checking doneness around 28 minutes. The from-scratch version is richer, but shortcuts totally work on busy days.

How do I know when these bars are done?

Look for a golden, set cookie top with slightly puffed edges and a toothpick that pulls out with moist crumbs, not wet batter. The center may still look a touch soft—that sets as it cools. Overbaked bars lose the fudgy magic.

Can I make them ahead?

Absolutely. Bake, cool, and slice, then store airtight at room temp up to 3 days or refrigerate up to 6 days. For events, bake the day before and chill; they slice cleaner and taste even better the next day.

What if I only have an 8-inch pan?

You can use an 8-inch square pan for thicker bars. Add 5–8 minutes to the bake time and tent with foil if the top browns too fast. Cool completely so the center sets before slicing.

Can I make them egg-free?

Try 1/4 cup plain yogurt or a flax egg (1 tbsp ground flax + 3 tbsp water, set 5 minutes) for the cookie layer, and the same flax egg swap for the brownie eggs. Expect a touch less lift but plenty of fudgy chew.

Will oil work instead of butter?

Use neutral oil in the brownie layer (same weight) for extra fudgy texture. For the cookie layer, butter is best for flavor and structure, but you can try half butter, half oil to keep it tender without losing shape.

How do I keep the cookie pieces crunchy?

Reserve some chopped cookies for sprinkling on top before baking and again right after it comes out of the oven. The double-hit plus a short rewarm at 300°F later helps maintain that signature crunch.

What’s the yield and best cut size for parties?

The recipe comfortably yields 16 large bars or 25 bite-size squares. For dessert boards, cut into 1.5-inch pieces so guests can sample other treats, too.

My Take

Some desserts are good, and some are disappearing-act good—these live in the second camp. The layered format means you get brownie comfort and cookie nostalgia, then the cookie-and-cream crunch throws it over the top. It’s maximalist without being fussy, which, IMO, is the sweet spot for home baking. Keep a pan in the freezer for last-minute invites and you’ll look like you planned it all along.