Oreo Layer Cake with Cookies & Cream Buttercream and Ganache – Ultimate Homemade Dessert

If you’re anything like me, you have a serious soft spot for Oreos.

That rich chocolate cookie and sweet creamy filling is a match made in dessert heaven.

This cake takes everything we love about Oreos and turns it into a layered masterpiece you’ll want to make again and again.

It’s rich, moist, and filled with a light Oreo buttercream that’s so good, you’ll be licking the spoon.

Whether you’re baking for a birthday, a party, or just because—it’s guaranteed to be a hit.

Nostalgic Appeal

Growing up, Oreos were my favorite treat.

I’d always pull them apart, eat the filling first, and save the cookie for last.

They were my comfort food, my after-school snack, and my go-to whenever I needed something sweet.

Now as an adult, I still adore them—but this cake takes that childhood love and gives it an elevated, homemade twist.

Homemade Focus

There’s nothing store-bought about this cake, and that’s exactly what makes it so special.

From the dark chocolate sponge to the silky Oreo buttercream and the glossy ganache drip—it’s made 100% from scratch.

But don’t worry—it’s not complicated.

It’s a step-by-step process that anyone can follow, and the results? Absolutely worth it.

Flavor Goal

This cake is rich and chocolatey but not too sweet.

The balance comes from the dark cocoa, the subtle tang of buttermilk, and the creamy smoothness of the buttercream.

Every bite is loaded with Oreo flavor—crunchy, creamy, and perfectly nostalgic.

And the ganache drip? That’s just the cherry on top (or in this case, the glossy chocolate finish).

Ingredient Insights

The base of the cake uses all-purpose flour, paired with crushed Oreo cookies for that signature taste.

Dutch-processed and black cocoa powders create that deep, intense chocolate flavor that mimics the Oreo cookie.

Baking soda and baking powder help it rise, and salt brings everything into balance.

Buttermilk and hot coffee keep the cake moist and enhance the cocoa.

Eggs and vanilla add richness and structure.

For the buttercream, we’re using egg whites and sugar cooked into a meringue, then whipped with butter to create a smooth and light frosting.

Sifted Oreo crumbs get folded in for that cookies-and-cream texture.

The ganache is a simple combo of dark chocolate and heavy cream, with optional black gel to deepen the color.

And of course, extra Oreos—because more is always better.

Essential Equipment

You’ll need three 6-inch round cake pans and parchment paper.

A stand mixer is helpful, especially for the buttercream, though a hand mixer can work too.

An offset spatula makes it easy to smooth the frosting and ganache.

You’ll also want a piping bag with a star tip to create those beautiful rosettes on top.

A digital scale can help divide the batter evenly, but isn’t required.

Ingredients with Measurements

Chocolate Cake

• 1 cup all-purpose flour

• ½ cup Oreo cookie crumbs (sifted)

• 1½ cups granulated sugar

• 6 tbsp Dutch-processed cocoa powder (sifted)

• 6 tbsp black cocoa powder

• 1½ tsp baking soda

• 1 tsp baking powder

• 1 tsp salt

• ¼ cup vegetable oil

• ¾ cup buttermilk

• ¾ cup hot water or hot coffee

• 2 large eggs

• 2 tsp vanilla extract

Oreo Buttercream

• 6 large egg whites

• 2 cups granulated sugar

• 2 cups unsalted butter, room temperature

• 1 tsp clear vanilla extract (optional)

• 1 cup Oreo cookie crumbs (sifted)

Ganache Drip

• 3 oz dark chocolate, chopped

• 3 oz heavy cream

• 1–2 drops black gel food coloring (optional)

Assembly

• 10 chopped Oreos

• Mini Oreos for decoration (optional)

Step-by-Step Instructions

Make the Cake Layers

1. Prep Your Pans
Preheat the oven to 350°F (175°C).

Grease and cocoa-dust three 6-inch pans and line the bottoms with parchment.

This prevents sticking and keeps your layers clean.

2. Mix Dry Ingredients
In the bowl of your stand mixer, stir together the flour, sugar, Oreo crumbs, cocoa powders, leaveners, and salt.

It should look like a rich, dark cocoa mix.

3. Mix Wet Ingredients
In a separate bowl, whisk together oil, buttermilk, hot coffee, eggs, and vanilla.

Slowly pour this into the dry ingredients while the mixer runs on low.

Mix for 2–3 minutes until smooth and slightly runny.

4. Bake the Cake
Divide the batter evenly into the pans.

Bake for 30–35 minutes, or until a toothpick comes out with a few moist crumbs.

Cool in the pans for 10 minutes, then transfer to wire racks.

Once cooled, slice each layer in half horizontally—you’ll have 6 layers total.

Make the Oreo Buttercream

1. Cook the Egg Whites & Sugar
In your stand mixer bowl, combine egg whites and sugar.

Place it over a pot of simmering water and whisk constantly for about 3 minutes.

It’s ready when the sugar is fully dissolved and the mixture feels smooth.

2. Whip the Meringue
Attach the bowl to your mixer and whip until stiff peaks form and the bowl is no longer warm.

This usually takes 5–10 minutes.

3. Add Butter & Flavoring
Switch to the paddle attachment.

Add cubed butter slowly and beat until it becomes smooth and fluffy.

Add vanilla if using.

4. Add Oreo Crumbs
Scoop out about 1 cup of plain buttercream and set aside.

Fold in the Oreo crumbs to the rest of the frosting and mix until evenly distributed.

Make the Ganache

Heat the heavy cream in the microwave until hot but not boiling.

Stir in the chopped chocolate and let it sit for a minute.

Add a drop or two of black gel food coloring if you want a deeper shade.

Stir until smooth, glossy, and completely melted.

Let cool until slightly thickened—it should drip slowly, not run.

Assemble the Cake

1. Layer the Cake
Place the first layer on your cake board or stand.

Spread about ⅔ cup of Oreo buttercream on top.

Sprinkle chopped Oreos over the frosting.

Repeat with all layers.

2. Crumb Coat and Chill
Cover the whole cake in a thin layer of frosting.

Refrigerate for 20 minutes to firm up.

3. Final Frosting
Frost the cake with the rest of the Oreo buttercream.

Use a bench scraper or offset spatula to smooth the surface.

Chill again for 30 minutes.

Add the Ganache and Decorate

1. Ganache Drip
Use a spoon to drip ganache around the top edges of the cake.

Pour the rest on top and smooth it gently.

Let it set for a few minutes.

2. Add Rosettes and Mini Oreos
Place the reserved plain buttercream in a piping bag fitted with a 1M tip.

Pipe rosettes around the top edge.

Top each swirl with a mini Oreo for a fun finish.

Tips & Variations

Add chopped Oreos between the cake layers for crunch.

Use chocolate chips in place of ganache if you prefer a chunkier texture.

Turn this into cupcakes by baking for 18–20 minutes and piping the Oreo buttercream on top.

To lighten the cake, replace some of the butter with cream cheese for a tangy twist.

Serving & Pairing Suggestions

Serve at room temperature for the creamiest buttercream texture.

Pair with a glass of milk, cold brew coffee, or a scoop of cookies and cream ice cream.

Perfect for birthdays, parties, or as a showstopper centerpiece at any dessert table.

Your guests will be begging for the recipe.

Nutrition Info (Per Slice – 12 Servings)

• Calories: 715

• Fat: 42g

• Carbs: 81g

• Sugar: 63g

• Protein: 7g

• Sodium: 312mg

• Cholesterol: 106mg

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Recipe Summary & Q&A

This Oreo Cake is a dream dessert for anyone who loves cookies and cream.

The layers are moist and chocolatey, the buttercream is smooth and rich, and the ganache gives it an elegant finish.

It’s surprisingly easy to make, completely from scratch, and the flavor is unforgettable.

Can I use store-bought frosting?
You can, but homemade Swiss meringue buttercream gives a much smoother, less sweet result.

Can I make it ahead?
Yes—bake and frost the day before. Add ganache and decorations the day of serving.

How do I store leftovers?
Keep the cake in the fridge, covered. Bring to room temp before serving.

Can I freeze it?
Absolutely. Freeze slices wrapped tightly for up to one month.