For the Moist Chocolate Cake Layers (4 x 8-inch round cakes):

• 3 cups (375g) all-purpose flour
• 3 cups (600g) granulated sugar
• 1 cup (100g) unsweetened cocoa powder (Dutch-processed recommended)
• 3 teaspoons baking soda
• 1 ½ teaspoons baking powder
• 1 ½ teaspoons salt
• 1 ½ cups (360ml) buttermilk (or 1 ½ cups milk + 1 ½ tbsp white vinegar/lemon juice)
• ¾ cup (180ml) vegetable oil
• 3 large eggs, at room temperature
• 1 ½ teaspoons vanilla extract
• 1 ½ cups (360ml) hot brewed coffee (strong)

For the Cream Cheese Frosting (Light Filling & Outer Coat):

• 16 oz (2 blocks, 450g) cream cheese, softened
• 1 cup (226g) unsalted butter, softened
• 6–7 cups (720-840g) powdered sugar (icing sugar), sifted
• 2 teaspoons vanilla extract
• 2–4 tablespoons milk or heavy cream (as needed for consistency)
• Pinch of salt

For the Oreo Cookie Cream Filling (Darker Filling):

• 8 oz (1 block, 226g) cream cheese, softened
• ½ cup (113g) unsalted butter, softened
• 1 ½ cups (180g) powdered sugar, sifted
• 1 teaspoon vanilla extract
• 1 cup (about 12–15 cookies) Oreo cookie crumbs (finely crushed, with cream)
• 2–3 tablespoons milk or heavy cream

For the Chocolate Ganache Drizzle:

• 1 cup (240ml) heavy cream
• 8 oz (226g) good quality semi-sweet or dark chocolate, finely chopped

For Garnish:

• 3–4 chocolate truffles or chocolate spheres
• 3–4 whole Oreo cookies
• ¼ cup crushed Oreo cookies

Equipment:

• Four 8-inch round cake pans
• Parchment paper
• Wire racks
• Electric mixer
• Saucepans or microwave-safe bowls
• Spatulas, offset spatula
• Cake turntable