Chocolate Cake with Oreo Buttercream
This week I fell into a trap. During my weekly family visit, my niece Amal came and sat on my lap, as she usually does when I’m there. Out of the blue, she asked me to make her a birthday cake. I immediately said yes. On one hand, it’s hard to say no to those beautiful big brown eyes. On the other hand, her birthday is in July, so there’s a lot of time till then.
“You remember that your birthday is not so soon, right?” I asked. “Right, but I’m celebrating my birthday at school this week!” She said. With all the other kids whose birthdays fell during the summer break. And it turns out my sister was in charge of bringing a birthday cake for the whole class. There was no way out of it. I looked at Amal and promised her a beautiful birthday cake.
I didn’t have much time to plan. Due to the holidays, I had to think fast and get all the ingredients in advance before the stores closed. I decided to make a cake that I have already made before: a tall chocolate cake with Oreo buttercream.
I recently perfected the buttercream recipe — perfect timing for the cake, and this post. The buttercream is similar to the buttercream I used in Ilana and Romy’s wedding cake, but in this cake I substituted most of the mascarpone cheese for white chocolate. I think the birthday kids and their friends will appreciate that more.
When I made this cake there was a lot of extra Oreo buttercream left over. I may have miscalculated the amount of buttercream needed for this recipe. No biggy, I’ll try to remember that next time and update this post accordingly. With eight nephews and nieces and birthdays scattered all over the yearly calendar, I’m sure I’ll use this recipe once more.
* The wonderful recipe for the chocolate cake is from add a pinch with some slight changes in the preparation process.
450 g flour
130 g cocoa powder
3 tsp baking powder
2 tsp baking soda
700 g sugar
1½ tsp salt
4 medium eggs (160 g)
160 g canola oil
2 tsp vanilla extract
360 g milk
320 g boiling water
1½ tsp instant coffee
Oreo Swiss meringue buttercream
6 egg whites (L)
1½ cup sugar
340 g soft butter at room temperature
330 g mascarpone at room temperature
8 Oreo cookies (about 88 g)
A pinch of salt
“Ice cream” scoop
100 g leftover chocolate cake
1 heaping tsp of Oreo buttercream
100 g dark chocolate
100 g heavy cream
Ice cream cone
3-4 Oreo cookies
2 baking pans, 15 cm diameter and 10 cm height *
* If there’s only one cake pan, divide the chocolate cake recipe in half and bake twice.
Lightly grease pans with oil. Line pans with parchment paper by cutting two circles, 15 cm in diameter each for the bottom, and a rectangle to fit the sides of the pans.
Sift flour, cocoa powder, baking powder and baking soda into a bowl. Add sugar and salt. Mix until uniform. Set aside.
Preheat oven to 175º C (350º F). Whip the eggs on medium speed until you get a foamy texture. Add canola oil and vanilla extract and mix until uniform. Bring water to a boil.
Add a third of the powder mixture to the egg batter and mix until uniform. Please note (!) Once the flour is combined in the batter, do not over mix. Pour half of the milk and mix again. Add another third of the powders and mix. Pour the rest of the milk and mix. Finally, add the rest of the powders and mix until the batter is uniform.
Add instant coffee to the boiling water. Mix well and add carefully to the batter. Mix again until uniform. Pour the batter evenly into both pans. If possible, wrap a strip of a damp towel around the baking pan to get a more uniform bake.
Put the two pans in an oven preheated to 175º C (350º F) and bake for 55-60 minutes. Stick a toothpick in the center of the cake to check if it’s ready. The toothpick should come out almost dry, with just a bit of crumbs.
Remove pans from the oven and keep the cakes at room temperature for 10-15 minutes before releasing from the pans. Let the cakes cool completely at room temperature and then keep in the fridge until ready to cut. (The cakes can be kept in the fridge for about a week or in the freezer for about a month)
Cut each cake twice to a height of 4 cm with a large serrated knife or a saw. You should get two 4 cm-high layers from each cake (4 layers in total). To get a straight clean cut, keep turning the cake and cut first from the sides then slowly advance to the center of the cake. Set aside the remaining scraps. Remove the parchment paper from the bottom of the cakes. Cover each layer in plastic wrap. Keep in the fridge until use.
Oreo swiss meringue buttercream
Put egg whites and sugar in a steel bowl. Set on a double boiler and heat on medium heat while whisking all along. When the mixture’s temperature reaches 70 ºC (160 ºF), lower the flame (or even turn it off) and continue whisking for a one more minute. This way the eggs get pasteurized. Remove from heat and allow it to cool at room temperature.
In the meantime, put soft butter in a bowl and whip (using a hand mixer or a stand mixer) for about half a minute. Add mascarpone gradually and continue to whip until the texture is smooth and fluffy, about 5 minutes. If some liquid forms in the bowl when adding the mascarpone, just get rid of it and continue to whip (This could be avoided if the ingredients have the same temperature).
When the temperature of the egg white mixture reaches 40 ºC (105 ºF), strain it directly into the bowl of the butter and mascarpone. Whisk everything together until you get a smooth and silky cream (About 5 minutes). Add a pinch of salt. In a food processor, grind the Oreo cookies into small crumbs. Add the Oreo crumbs to the buttercream and fold until uniform.
Putting it together!
There are two ways to cover the cake with the buttercream. The first is relatively simple and the second is slightly more complex but more accurate. For this cake I used the second method which requires 2 round glass/plastic boards with a 16 cm diameter.
In this method, the cake is assembled with a board on top and on bottom, and then covered in cream. The boards give you more control over the buttercream cover and produce a nice straight cake without too much effort. Since not everybody has these boards, I’ll explain how to cover the cake using the simpler method, without the boards.
Spread a little bit of buttercream in the center of a serving plate, which will serve as the glue to keep the cake in place on the plate. Place one of the cake layers on top. Spread a layer of buttercream over the cake (at least 1 cm thick please, your friends and family will thank you later). Flatten the surface with a spatula.
Repeat the process for the other layers:
Place the second cake layer over the first one. Spread another layer of buttercream on top. Place the third cake layer over the second one. Spread another layer of buttercream on top. Place the fourth (and final) cake layer over the third one. Spread a very thin layer of buttercream on top.
Spread buttercream generously around the sides of the cake. Use a cake scraper to remove all the excess buttercream. To do so, press the scraper on the side of the cake while turning the cake around, leaving it with a smooth layer of buttercream around the cake. (If there are dents, fill them with buttercream and smooth them again with the scraper). Smooth the top edges as much as possible. Keep in the fridge for at least two hours until the buttercream has set.
“Ice cream” scoop
Put the cake leftovers in a bowl. Make sure your hands are clean. Crumble the cake leftovers into crumbs. Add a spoonful of Oreo buttercream and mix well (that’s actually how you make cake pops!). Use the mixture to make a ball the size of an ice cream scoop. Place it in the center of the top of the cake.
Break the chocolate into small pieces and put them in a measuring pitcher. Bring the heavy cream to a boil and pour over chocolate, making sure all the chocolate is covered. Mix a little bit with a spatula and then use a hand blender to blend it to a uniform consistency. Let the ganache cool just a little and then transfer it into a bowl.
Remove the cake from the fridge. Using a teaspoon, spread a little bit of chocolate ganache on the edge around the top of the cake. Gently push the ganache over the edge to create a drip effect. Spread some more ganache over and around the “ice cream” scoop. Flatten the surface with a spreading spatula.
Grind the Oreo cookies to a powder. Decorate the bottom of the cake with a bit of the Oreo powder. Spread a strip of chocolate ganache around the edge of the ice cream cone. Decorate it with Oreo powder too. Set the cone on top of the “ice cream” scoop, tilted just a little. Keep the cake in an airtight container (on a tall shelf) in the fridge up to a week.
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