Ingredients

For the cake

• 2 cups all‑purpose flour (240g)

• 1 cup granulated sugar (200g)

• ¼ teaspoon baking soda

• 1 teaspoon baking powder

• ¼ teaspoon kosher salt

• ¾ cup unsalted butter, room temp (170g)

• 3 large egg whites

• 1 teaspoon vanilla extract

• ½ cup sour cream, room temp (120g)

• ½ cup whole milk, room temp (120mL)

• 1 cup chopped Oreos (120g)

For the buttercream

• 1½ cups unsalted butter, room temp (340g)

• 5 cups confectioners’ sugar (600g)

• 1⅓ cups crushed Oreos (165g)

• ¼ cup heavy cream (60mL)

• Pinch salt

For the ganache

• 1 cup semisweet chocolate chips (180g)

• ½ cup heavy cream (120mL)

Direction

For the cake

• Preheat oven to 350°F. Butter and flour three 6‑inch pans; line bottoms with parchment.

• Sift flour, sugar, baking soda, baking powder, and salt in a large bowl.

• Beat butter on medium until light and fluffy (about 1 minute).

• Add dry ingredients to butter; mix on low until crumbly.

• Whisk egg whites, sour cream, milk, and vanilla in a separate bowl.

• Add wet mixture to dry mixture; beat on low until fluffy (about 30 seconds).

• Fold in chopped Oreos gently.

• Divide batter evenly among pans.

• Bake 25–30 minutes, until centers are springy.

• Cool completely in pans, then remove.

For the buttercream

• Beat butter on medium until light and fluffy (about 2 minutes).

• Add confectioners’ sugar and cream gradually on low speed.

• Mix until smooth and fluffy.

• Reserve 1 cup for white dollops; place in piping bag with open star tip (#869).

• Mix crushed Oreos into remaining buttercream.

For the ganache

• Heat cream in microwave until steaming (about 1 minute).

• Combine chocolate and hot cream; microwave at 50% power in 20‑second intervals, stirring each time, until smooth.

• Let cool slightly.

For the assembly

• Spread a heaping ⅓ cup Oreo buttercream on first cake layer; add a swirl of ganache.

• Add second layer; repeat buttercream + ganache.

• Add final layer; frost entire cake with Oreo buttercream.

• Optional: press crushed Oreos around the bottom edge.

• Chill cake for 30 minutes.

• Rewarm ganache 5–10 seconds if needed; pour over top and let drip down sides.

• Smooth top with offset spatula.

• Pipe white buttercream dollops on top.

• Chill 1 hour before slicing.

Notes

• Don’t chop Oreos too finely — larger pieces keep crunch and prevent grey batter.

• Keep Oreo filling — it adds flavor and saves time.

• Cutting for a crowd? Use proper round‑cake slicing technique for even portions.

Nutrition

Calories: 1142kcal Carbohydrates: 137g Protein: 8g Fat: 65g Saturated Fat: 38g Polyunsaturated Fat: 4g Monounsaturated Fat: 19g Trans Fat: 2g Cholesterol: 139mg Sodium: 312mg Potassium: 296mg Fiber: 3g Sugar: 102g Vitamin A: 1640IU Vitamin C: 0.2mg Calcium: 98mg Iron: 7mg