Slutty Brownies: Fudgy Oreo-Stuffed Cookie Bars

The first bite is a layered hit of crisp cookie, a chocolate-creamy Oreo center, and a dense, fudgy brownie — that contrast is why Slutty Brownies are irresistible. Slutty Brownies are a mash-up dessert that became an internet favorite for their simplicity and big payoff. After testing this version eight times and tweaking bake times, I landed on a reliable method that gives a chewy brownie, a fully baked chocolate cookie base, and an intact Oreo layer every time. This recipe is the one I teach home bakers when they want wow-factor dessert with almost no fuss. Read on for clear steps, exact measurements in both metric and imperial units, and pro tips to avoid soggy middles or burned edges.

Why This Recipe Works

Layering ingredients with balanced moisture prevents a soggy middle while keeping a fudgy brownie layer.
Slightly undermixing the brownie batter keeps it dense and gooey instead of cake-like.
Chilling the cookie dough for a short time firms it so it bakes through without overbrowning.
Using whole eggs and melted butter in the brownie creates a glossy, fudgy crumb.
Testing different pan sizes confirmed a 9×9-inch pan gives even bake and correct thickness.

Ingredients Breakdown

Cookie dough layer
200 g (1 cup) unsalted butter, softened — provides richness; do not substitute with margarine.
200 g (1 cup) brown sugar, packed — adds chew and deeper flavor; white sugar will make it less moist.
100 g (1/2 cup) granulated sugar — balances sweetness and helps spread.
1 large egg — binds; for egg-free, see Variations.
300 g (2 1/2 cups) all-purpose flour — structure. If using a lighter flour, reduce by 1 tbsp.
1 tsp (5 g) baking powder — light lift so cookie base bakes through.
1/2 tsp (3 g) Diamond Crystal kosher salt* — brand matters for volume; if using Morton’s, use 3/4 tsp.
5 ml (1 tsp) vanilla extract — flavor.
Oreo layer
16 Oreo cookies (about 260 g total) — classic texture contrast; you can use gluten-free sandwich cookies in a GF version.
Brownie layer
170 g (6 oz) bittersweet chocolate, chopped — gives deep chocolate flavor.
115 g (1/2 cup) unsalted butter — melted with chocolate for gloss.
200 g (1 cup) granulated sugar — sweetness and structure.
2 large eggs — gives fudgy texture.
60 g (2/3 cup) all-purpose flour — just enough to set the brownie without making it cakey.
1 tbsp (15 ml) strong coffee or espresso (optional) — intensifies chocolate.

Notes and substitutions:

You can substitute Greek yogurt for part of the butter in the cookie dough, but the cookie will be less rich and slightly tangy.
For a dairy-free version, use a high-fat dairy-free butter and dairy-free chocolate; texture will be a touch different.
Using real butter and good quality chocolate materially affects flavor and texture.

Essential Equipment

23 cm x 23 cm (9 x 9-inch) square baking pan — a smaller 8-inch pan will overflow; a larger 10-inch pan will make layers thin.
Parchment paper with overhang — for easy lift and clean edges.
Medium saucepan or heatproof bowl for melting chocolate.
Rubber spatula and whisk.
Digital scale — weights produce consistent results.
Oven thermometer (recommended) — home ovens can run hot or cold; accuracy matters.

If you don’t have a 9×9 pan, use a 20 x 20 cm square pan and check for doneness a few minutes earlier.

Step-by-Step Instructions

Prep time: 20 minutes; Cook time: 25–30 minutes; Inactive time: 15 minutes chilling; Total time: ~1 hour (including cooling); Servings: 12 bars.

Step 1: Make the cookie dough base

Preheat the oven to 175°C (350°F). Cream 200 g (1 cup) softened unsalted butter with 200 g (1 cup) packed brown sugar and 100 g (1/2 cup) granulated sugar until light, about 2–3 minutes. Add 1 large egg and 5 ml (1 tsp) vanilla and whisk until combined, then stir in 300 g (2 1/2 cups) all-purpose flour, 1 tsp (5 g) baking powder, and 1/2 tsp (3 g) kosher salt until just combined. Do not overmix — stop as soon as no dry flour is visible.

Step 2: Press the cookie dough into the pan

Line a 23 x 23 cm (9 x 9-inch) pan with parchment. Press two-thirds of the cookie dough evenly into the bottom, creating a solid base, about 6 mm (1/4 inch) thick. Reserve the remaining dough in the fridge while you prepare the other layers, about 10–15 minutes to firm up.

Step 3: Add the Oreo layer

Arrange 16 Oreo cookies in a single layer on top of the pressed cookie dough. Fit them edge-to-edge with little gaps; they will soften but retain shape.

Step 4: Make the brownie batter

In a heatproof bowl over barely simmering water or in the microwave, melt 170 g (6 oz) chopped bittersweet chocolate with 115 g (1/2 cup) unsalted butter until smooth, about 2–3 minutes stirring every 30 seconds. Whisk in 200 g (1 cup) granulated sugar, then add 2 large eggs one at a time, whisking 20–30 seconds after each so the batter becomes glossy. Fold in 60 g (2/3 cup) all-purpose flour and 1 tbsp (15 ml) coffee until just blended. Fold gently — overworking will aerate the batter and make it cake-like.

Step 5: Top and bake

Spoon the brownie batter over the Oreo layer and spread gently with an offset spatula. Crumble the reserved cookie dough and dot it over the brownie batter for a rustic top. Bake at 175°C (350°F) for 25–30 minutes, rotating the pan halfway. The center should be set but still slightly fudgy; a toothpick inserted near the center will come out with moist crumbs, not wet batter. If the edges brown too quickly, tent with foil after 20 minutes.

Step 6: Cool and slice

Cool the pan on a wire rack for at least 30 minutes; then refrigerate for 15 minutes to firm before lifting with parchment. Use a sharp knife warmed under hot water and wiped dry for clean slices. Cut into 12 equal bars.

Expert Tips & Pro Techniques

Common mistake: baking too long. Overbaking dries the brownie. Remove when the center still jiggles slightly and uses the toothpick moist-crumb cue.
Make-ahead: Bake the brownies, cool fully, wrap tightly, and refrigerate up to 3 days. Bring to room temp before serving or reheat briefly.
Professional trick for clean slices: chill for 15–30 minutes and use a hot, dry knife between cuts.
Adjusting oven variance: test with an oven thermometer; if your oven runs hot, drop temp by 10–15°C (20–25°F).
For extra fudginess: replace 1 tbsp of flour with 1 tbsp Dutch-processed cocoa powder.
If you want a different cookie base, try a sturdy chocolate chip cookie dough; see this related cookie-dough brownies method for inspiration: cookie-dough brownies recipe.

Storage & Reheating

Refrigerator: Store in an airtight container for up to 3 days. To keep the top from sticking, layer with parchment between layers.
Freezer: Cut into bars and freeze in a single layer on a baking sheet until solid, then transfer to a freezer-safe bag for up to 2 months. Thaw in the fridge overnight.
Reheating: Reheat at 175°C (350°F) for 6–8 minutes if cold from the fridge, or 10–12 minutes if frozen and thawed. Avoid microwaving — it makes the texture gummy.

Variations & Substitutions

Gluten-Free Version: Replace 360 g total flour equivalents with a 1:1 GF blend; add 1/2 tsp xanthan gum if your blend lacks binding. Bake time may increase by 3–5 minutes.
Vegan Version: Use plant-based butter, replace eggs with 2 flax eggs (2 tbsp ground flax + 6 tbsp water), and use dairy-free chocolate. Texture will be a touch denser.
Salted Caramel Twist: Drizzle 60 ml (1/4 cup) salted caramel over the brownie batter before adding cookie dough crumbs. Keep everything else the same.
Pistachio Brownie Variation: Swap half the Oreos for chopped roasted pistachios and fold 30 g (1/4 cup) finely chopped pistachios into the cookie dough; see a nut-focused idea here: pistachio brownies with pistachio.
Chocolate-mousse topping (lighter finish): After cooling, pipe a thin layer of chocolate mousse on top and chill 30 minutes; technique inspiration: chocolate mousse brownies.

Serving Suggestions & Pairings

A scoop of vanilla ice cream and a warm salted caramel sauce make these decadent for dessert; try pairing with our festive ideas for holiday brownie gifts: holiday brownie presents.
Serve with a strong black coffee or espresso to cut the sweetness.
Garnish with flaky sea salt or a dusting of cocoa for a bakery-style finish.
For a party platter, cut into smaller squares and mix with simple fruit to balance richness.

Nutrition Information

Per serving: 1 bar (recipe makes 12 bars)

Calories: 460 kcal
Total Fat: 25 g
Saturated Fat: 12 g
Cholesterol: 85 mg
Sodium: 230 mg
Total Carbohydrates: 58 g
Dietary Fiber: 3 g
Sugars: 38 g
Protein: 5 g

Nutrition values are estimates. Actual values may vary based on specific ingredients and preparation methods.

Frequently Asked Questions

Q: Why did my Slutty Brownies turn out dry? A: Most likely they were overbaked. Remove when the center still has moist crumbs and a slight jiggle. Oven temperature can vary; check 5 minutes before the end of the bake time.

Q: Can I make this without eggs? A: Yes. For two eggs, use two flax eggs (2 tbsp ground flax + 6 tbsp water, whisk and rest 5 minutes). Expect a slightly denser texture.

Q: Can I double this recipe? A: Yes. Use a 13 x 9-inch (33 x 23 cm) pan or two 9×9 pans. Baking time may increase by 5–10 minutes if using a single larger pan. Check doneness with the moist-crumb toothpick test.

Q: Can I prepare this the night before? A: Absolutely. Bake, cool, then wrap and refrigerate. Bring to room temperature or reheat briefly before serving.

Q: How long does this keep in the fridge? A: Up to 3 days in an airtight container. For longer storage, freeze up to 2 months; thaw overnight in the fridge.

Q: Can I use a different sandwich cookie instead of Oreos? A: Yes — any chocolate sandwich cookie will work. If the cookie is very thick, reduce the number slightly so layers stay balanced.

Q: My cookie layer stayed doughy. What happened? A: The cookie base may have been too thick or the oven too cool. Press the dough thin and even (about 6 mm / 1/4 inch) and ensure oven is fully preheated to 175°C (350°F).

Conclusion

These Slutty Brownies are a foolproof way to get a showstopping dessert with little technique and big flavor. For another twist on combining brownies and cheesecake, try this creamy cheesecake-brownies idea: cheesecake brownies recipe. If you want to compare versions or get extra step-by-step photos, these two classic takes are helpful references: Slutty Brownies Recipe – What’s Gaby Cooking and Slutty Brownies – Homemade, Fudgy, Delicious – Just so Tasty.