This cookies and cream cake is made with layers of vanilla sponge baked with pieces of chocolate sandwich cookies, with a rich chocolate buttercream filling. This will surely impress your guests!
Making the cookie sponges Preheat the oven to 170ºC. Grease three 18 cm round tins and line with parchment paper. Sift flour, baking powder and salt into a bowl and set aside. Add milk, vegetable oil and vanilla extract into a jug and mix to combine.
Fit the K-Beater. Add butter into the Appliance bowl. Mix for 2 minutes on speed 3, and then scrape the bowl. Add sugar. Mix for 5 minutes on speed 4. Add egg whites gradually while the machine is running. Mix for 2 minutes on speed 1, and then scrape the bowl. Transfer one third of the flour mixture and one third of the milk mixture into the Appliance bowl. Mix for 30 seconds on speed Min, until combined. Repeat the same steps with the remaining flour and milk mixture. Add chocolate sandwich biscuits. Mix for 30 seconds on speed Min, until combined. Divide the mixture between the three tins. Bake for 35-40 minutes at 170ºC, until a skewer inserted comes out clean. Remove from the oven and let cool completely.
Making the chocolate buttercream Clean the Appliance bowl and fit the Creaming Beater. Add butter into the Appliance bowl. Mix for 2 minutes on speed 3, until light in colour and then scrape the bowl. Add icing sugar and cocoa powder. Mix for 1 minute on speed Min. Mix for 2 minutes on speed 3. Add milk. Mix for 2 minutes on speed Min. Tip: Add more milk to loosen mixture if needed. Transfer the buttercream into a clean bowl and set aside.
Making the vanilla buttercream Clean the Appliance bowl and fit the Creaming Beater. Add butter into the Appliance bowl. Mix for 2 minutes on speed 3, until light in colour and then scrape the bowl. Add icing sugar. Mix for 1 minute on speed Min. Mix for 2 minutes on speed 3. Add vanilla extract and milk. Mix for 3 minutes on speed Min. Tip: Add more milk to loosen mixture if needed.
Making the dark chocolate buttons Line a work surface with parchment paper. Draw 10-12 circles, 3.5 cm wide, on the parchment paper. Add melted dark chocolate and melted black candy melts into a bowl. Stir until combined. Transfer the mixture into a piping bag and cut the end, about 0.5 cm in. Pipe the chocolate onto the paper template to make the buttons. Let cool until hardened.
Assembling the cake Trim the cooled sponge layers with a cake leveller or use a bread knife. Place the bottom sponge layer on a cake board and spread with half of the chocolate buttercream. Top with another sponge layer and spread with the rest of the chocolate buttercream. Place the last sponge layer on top. Crumb coat the top and sides of the cake with a thin layer of vanilla buttercream. Chill for 20-30 minutes in the fridge until set.
Decorating the cake Once set, coat the top and sides of the cake with another thin layer of vanilla buttercream. Transfer the remaining vanilla buttercream into a piping bag fitted with a large open star tip. Pipe rosettes of buttercream around the top of the cake. Then add crushed sandwich biscuits into a clean bowl. Hold the cake at an angle over the bowl and press the cookie crumbs around the sides of the cake. Arrange the chocolate buttons in the buttercream piping on top of the cake. Sprinkle the top of the cake with the remaining crumbs (optional). Chill for 20 minutes in the fridge, until set.
Serve.