This super fudgy chocolate brownie layer cake is filled with an edible cookie dough and frosted with extra fudgy chocolate buttercream. I'll show you how to make safe to eat cookie dough and create this showstopping celebration cake - definitely one of the best cakes I've made! The cake requires no mixer, and the frosting comes together in under 10 minutes.
3 Parts to this showstopping cake
- The cake part of this is super fudgy and moist. I adapted the recipe from my peanut butter chocolate cake, so you still get the dark and rich colour from the boiling water, but I decreased the amount of sugar.
- The cake is filled with two layers of cookie dough that is safe to eat. Learn how to make edible cookie dough that tastes just like the real thing.
- The cake is then frosted with a super fudgy chocolate frosting.
Let's review each part to this cake!
How to make a fudgy chocolate cake
This chocolate cake is super easy and doesn't require a mixer. Start off by whisking the oil, eggs, buttermilk and vanilla together in a large jug. In a large bowl, whisk together all the dry ingredients. Slowly pour in the buttermilk mixture and whisk (either by hand or with a mixer) until the batter is smooth. Then, add the boiling water (slowly!). This is what gives the cake such a dark and rich colour.
The batter for this cake is really thin, so don't worry if it appears a bit watery. Divide up your batter into three cake tins, about 22 ounces (600 grams) per tin. Allow the cake to cool completely before filling and frosting.
How to make edible cookie dough
Let's learn how to make safe to eat cookie dough! One of the main reasons you can't (I mean, I still do..) eat cookie dough before baking is due to the uncooked egg, but did you know you also need to heat treat the flour? This is a really simple step, where you bake the flour on a baking tray in an oven at 350 F/175 C for 5-10 minutes. Let the flour cool before using
Cream the butter with the sugar until super fluffy, then add the vanilla. Mix in the dry ingredients, and then add milk a tablespoon at a time until it reaches the consistency you want. Divide the dough in two and shape into discs, then wrap in clingfilm and refrigerate.
How to make fudge frosting
This super fudgy frosting is made with powdered sugar, butter, melted chocolate, salt, cocoa powder and heavy cream. It isn't as super sweet as American buttercream so it balances out the rest of the cake.
Start by beating the butter, cocoa powder, salt and powdered sugar together until fluffy. It'll start off looking quite sandy but keep beating it. Then add the remaining ingredients, adding the heavy cream a tablespoon at a time. Depending on the cocoa powder that you use, you might need to add a bit more to make the frosting fluffy and spreadable.
FAQ and Expert Tips
Bake your first two cakes, then allow them to cool for 10 minutes before taking the cakes out. Regrease one of the tins and line it with parchment paper, then bake the third layer.
Yes! You can make the cookie dough and cake 2 days in advance, just wrap tightly with clingfilm and store in the fridge. The frosting is best made on the day, otherwise you need to beat it again until fluffy.
Take a large sharp knife and run it under boiling water, quickly wipe dry with a paper towel, and make one slice. Repeat for each cut you make and you'll get a clean slice!
Add heavy cream a tablespoon at a time, and make sure you scrape the side of the bowl with a silicone spatula as some cream might get stuck at the bottom.
Put your cake on a large tray to catch the sprinkles. Take small handfuls of the sprinkles and toss it at the sides while the frosting is still fresh (sprinkles won't stick to frosting that has firmed up). Lightly press in the sprinkles.
This cake is best stored in the fridge, but let it get to room temperature when you want to cut it as the cookie dough firms up in the fridge.
You can easily make your own version of buttermilk by adding 1 tablespoon of vinegar or lemon juice to every cup of milk. Whisk together and leave for 5 minutes, then it's ready to use!
Want more cake recipes? Check these out!
Chocolate Brownie Cake with Cookie Dough Filling with Fudge Frosting
- 3 x 8 inch cake tins
- 112 grams cocoa powder 1 ¼ cup
- 330 grams flour 2 ¾ cups
- 360 ml boiling water 1 ½ cup
- 180 ml vegetable oil 1 cup
- 3 eggs
- 2 teaspoon vanilla extract
- 500 grams sugar 2 ½ cups
- 1 ½ teaspoon baking powder
- 1 teaspoon kosher salt
- 3 teaspoon baking soda
- 360 ml buttermilk 1 ½ cups
Cooke Dough Filling
- 330 grams butter, room temperature 1 ½ cups
- 225 grams light brown sugar 1 cup + 1 tbsp
- 225 grams sugar 1 cup + 1 tbsp
- 1 ½ teaspoon salt
- 2 teaspoon vanilla extract
- 292 grams flour, heat treated 2 ¼ cups
- 262 grams chocolate chips 1 ½ cups
- 3 tablespoon milk or heavy cream
- pinch nutmeg
- 270 grams powdered sugar 2 ⅕ cups
- 170 grams butter, room temperature 1 ½ sticks
- 4-5 tablespoon heavy cream
- 2 teaspoon kosher salt
- 30 grams cocoa powder ¼ cup
- 82 grams melted chocolate 3 ounces
- 2 teaspoon vanilla extract
- Preheat oven to 350°F/175°C. Grease 3 8-inch cake pans with butter, then line the bottoms with parchment paper.
- Combine the flour, cocoa powder, sugar, baking powder, baking soda, and salt in the bowl of a stand mixer, using the paddle attachment. Set aside. In a large jug, combine the buttermilk, oil, eggs and vanilla.
- While the mixer is on low speed, slowly pour in the wet ingredients. While mixer is till running, slowly add the boiling water and mix. Your batter will be very thin.
- Pour the batter into the prepared pans (about 22 ounces/600 grams per pan). Bake for 35-40 minutes, until a toothpick comes out clean when inserted.
- Allow the cakes to cool completely
Make Cookie Dough
- In a stand mixer with the whisk attachment, add butter and sugars, beat until fluffy and pale, about 2-3 minutes. Add the vanilla and mix again.
- Reduce the speed and slowly add in the flour, nutmeg and salt. Mix until just combined. Add in the milk/heavy cream a tablespoon at a time until you have your desired consistency. Fold in your chocolate chips.
- Divide the dough in two and shape into 8 inch circles. Wrap in clingfilm and keep in the fridge until ready to use.
Make Fudge Frosting
- In a stand mixer with the whisk attachment, beat the butter, powdered sugar, cocoa powder and salt together. Start on low and then increase the speed to stop the dry ingredients from flying out. Beat until fluffy, it will start off looking sandy but will come together. Pour in the melted chocolate, heavy cream and vanilla and beat for another minute.
- If the frosting isn't as spreadable as you would like, add more heavy cream a tablespoon at a time.
- Heat treat your flour: preheat your oven to 350 F/ 175 C and spread the flour for the cookie dough evenly on a baking sheet. Bake for 5-10 minutes. Cool completely.
- It's best to use the frosting immediately rather than storing in the fridge before assembling the cake.