In a mixer fitted with a paddle attachment, beat the sugar and butter for about 10 minutes until it becomes paler and fluffy.

With the mixer on medium speed, add the vanilla. Then add one egg at a time until everything is combined.

In a separate bowl, mix together the dry ingredients.

Take the mixture off the mixer and fold in the dry ingredients using a large metal spoon until it is well combined.

Divide the batter equally into 3 six-inch round cake pans lined with parchment paper and greased (about 300g in each tin).

Bake at 180°C for about 25-30 minutes until a skewer comes out clean when inserted into the center.

Let the cakes cool in the pan, then transfer them onto a wire rack to cool completely.

In the bowl of a standing mixer, add the sugar and egg whites. Heat this over a pan of water on medium heat until the sugar is dissolved.

Rub it with your fingers to test if the sugar has dissolved.

Beat using the whisk attachment on your standing mixer for about 15-20 minutes until the mixture comes to room temperature and the bowl is completely cool to the touch.

Add the butter in cubes, piece by piece, on medium speed until all the butter is incorporated.

Add vanilla and beat to combine. Then, add 1 cup of Oreo cookie crumbs/dust and mix to combine.

Separate 1 cup of the finished buttercream for swirls on top. Fill and frost the cake with the remaining buttercream.

While the cake frosting is still soft, add Oreo cookie crumbs to the bottom half of the cake.

Refrigerate the cake while you make the chocolate drip.

For the ganache, add chocolate and cream to a heat-proof bowl. Heat this in the microwave at 30-second intervals until it is fully combined.

Add the ganache to a piping bag or squirt bottle. Let it cool slightly so it won’t melt the frosting, but is still pourable.

Drizzle the chocolate ganache over the cooled cake. Finish the décor with buttercream swirls and more Oreo cookies.