Heat oven to 180 C / 160C Fan / Gas 4 and grease and line two 8” pans with baking parchment.
Using an electric hand-whisk or free standing mixer, beat the butter and sugar together until pale and fluffy. Whisk in the eggs one at a time, scraping down the sides of the bowl after each addition. Add the flour, Dr. Oetker Baking Powder, Dr. Oetker Cocoa Powder, salt and Dr. Oetker Madagascan Vanilla Extract, then fold until just combined. Fold in the milk. Divide the mixture into the two cake tins and smooth the top of the cake.
Bake for 35-40 minutes, until the cakes have risen and a skewer inserted into the middle of each cake comes out clean. Leave to cool on a wire rack for 20 minutes before removing from the tins. Allow the cakes to completely cool before moving on to the next step.
Take the two cooled cakes and trim the top of each cake to allow for a flat even surface. Cut each cake into two cakes using a sharp serrated knife, resulting in four even cake layers.
Place a layer of sponge on a cake board or serving dish and spread the chocolate buttercream on top, spreading the buttercream to the edges of the sponge. Place a sponge layer on top and repeat the above until all 4 layers of sponge are sandwiched together.
Once the cake is assembled, spread a thin layer of chocolate buttercream using a palette knife around the edges and on top of the cake to create a crumb coat. Then place the cake in the fridge for 30 minutes.
Once the crumb coat has set spread a thick layer of chocolate buttercream around the edges and top of the cake to achieve a smooth finish.
Sprinkle the Glamour and Sparkle Sprinkles on top of the cake.