Best ever moist Chocolate Slab Cake

Moist chocolate slab cake

The best ever moist chocolate slab cake has a chocolatey rich flavor with a deliciously fudgy buttercream icing that isn’t too sweet to go for seconds. 

The original chocolate layer cake was one of Mummy Rachel’s specialities and relatives would come to our home from far and wide for a slice on Eid day. 

It is an easy to make chocolate slab cake and everything gets mixed together before you add the self rising flour. For a cake flour chocolate cake please check the recipe for the delectable and Decadent Chocolate Cake with ganache frosting.

Mummy Rachel’s original cake was a double layer chocolate cake sandwiched with a slick of apricot jam and a thin layer of frosting. The top layer was then covered with more frosting that she forked a pattern on and simply decorated with glaced whole cherries. 

One day Mummy Rachel made chocolate slab cake with a creamy frosting for the tea that was held after the funeral of a family friend. It was without a doubt the best ever moist chocolate slab cake I had ever eaten. I must confess that I may have consumed at least three pieces (if not more) during the course of the afternoon tea. I don’t even recall eating anything else because my taste buds only seemed to be craving more and more of the chocolate slab cake. 

Moist chocolate slab cake

When Simone asked for an easy chocolate slab recipe that could be made with the minimum of fuss and effort, I knew this was the one. I have tweaked Mummy Rachel’s recipe slightly with the addition of coffee to the chocolate slab cake recipe.

The ingredients for the icing in the original recipe were a bit vague and this one is more reminiscent of the chocolate slab cake that I gorged on many years ago. My chocolate buttercream frosting was inspired by something my mother made when I was in Grade 7. The day before our teacher’s 50th birthday we decided we would have a party for him at school and everyone would bring something. I was asked to bring a birthday cake.

Moist chocolate slab cake

With only pantry staple ingredients my brilliant mother made what she called a chocolate sandwich cake, and insisted that the buttercream icing on the cake should contain actual chocolate too. It was hands down the best ever chocolate cake but we never wrote down the recipe, and after a few weeks completely forgot how much of each ingredient she used.

The combination of espresso and chocolate was one that first caught my eye when I tasted Bicerin (Torinese coffee), a coffee and chocolate drink, in Turin a few years ago. We tasted two different versions on the Dessert tour. My favorite was served in a small cup lined with chocolate hazelnut spread into which a shot of hot espresso is poured before it is topped with chantilly cream. 

Moist chocolate slab cake squares

Top tips for making a chocolate slab cake

  • Ensure that the ingredients like butter and eggs are at room temperature. The butter will bond easily with the sugar and result in a light and airy cake with a fine texture. 
  • Don’t panic if the butter, sugar and egg emulsion split. The eggs were possibly too cold or too many to be sustained by the butter and sugar emulsion. This won’t affect the end result and will be fine as soon as you add the flour. 
  • Line the baking sheet with parchment paper or ensure that it is thoroughly greased before baking to prevent sticking to the baking sheet. If you are not using parchment paper spray the inside of the tin with floured baking spray.

How to make a chocolate slab cake

How to make chocolate buttercream frosting

Moist chocolate slab cake

Best ever moist Chocolate Slab Cake

Razena Schroeder
The best ever moist chocolate slab cake has a chocolatey rich flavor with a deliciously fudgy buttercream icing that isn't too sweet to go for seconds. 
4.46 from 11 votes
Prep Time 45 minutes
Cook Time 30 minutes
Cooling time 1 hour
Total Time 2 hours 15 minutes
Course Cakes
Cuisine Cape Malay
Servings 20
Calories 471 kcal


Chocolate tray bake

  • 250 grams lightly salted butter soft at room temperature
  • 200 grams fine granulated sugar approximately 250 ml or 1 cup
  • 4 eggs, large at room temperature
  • 60 ml sunflower oil approximately 1/4 cup
  • 5 ml vanilla extract approximately 1 teaspoon
  • 350 grams self raising flour, approximately 562.50 ml or 2 1/4 cups
  • 5 ml baking powder approximately 1 teaspoon
  • 50 grams cocoa powder approximately 125 ml or 1/2 cup
  • 5 ml espresso instant coffee granules approximately 1 teaspoon
  • 125 ml hot water approximately 1/2 cup
  • 125 ml cold milk approximately 1/2 cup

Chocolate buttercream icing

  • 250 grams lightly salted butter soft at room temperature
  • 390 grams icing sugar, sifted approximately 750 ml or 3 cups
  • 65 grams cocoa powder approximately 185 ml or 3/4 cup
  • 5 ml vanilla extract approximately 1 teaspoon
  • 100 grams 70% cocoa chocolate, melted and cooled approximately 1 slab (we use Lindt)
  • 60 ml fresh cream approximately 1/4 cup


  • 60 grams pecan nuts halves and chopped for sprinkling


How to make chocolate slab cake

  • Heat the oven to 180 degrees Celcius or 160 fan / 350 F / Gas mark 4.
  • Beat the butter, sugar and eggs together until the sugar is dissolved and the mixture is light and creamy. Scrape down the sides every few minutes to incorporate the batter on the sides and bottom of the bowl. This may take between 7-10 minutes depending on the type of stand mixer you are using.
  • Add the oil and vanilla extract and beat for another minute.
  • Mix the instant espresso powder and 125 ml hot water, then and add the milk and stir together.
  • Stop the mixer and sift in most of the self rising flour, baking powder and cocoa. Mix in the dry ingredients until combined for another 2-3 minutes.
  • Add the warm espresso coffee mixture and beat until incorporated, for another minute.
  • Add in the last bit of flour and mix until combined.
  • Spoon into a greased baking sheet tin and bake for 25-30 minutes or until a toothpick comes out clean when inserted into the center of the cake. It may require a shorter baking time if you are using a fan assisted oven.
  • Leave the cake to cool completely before decorating with the chocolate buttercream frosting.

Chocolate buttercream frosting

  • Beat the butter for 3-5 mins until creamy and light in color.
  • Add the sifted icing sugar, cocoa powder, salt, vanilla extract and beat until fluffy for at least 1-2 minutes.
  • Add the cooled melted chocolate and cream and beat again until combined.
  • Spread the frosting over the cooled cake and decorate with edible flowers or nuts.
  • Cut into squares and serve with tea or coffee.


  • This recipe can also be used for two 9 inch (23 cm) round sandwich cakes to make a layer cake.
  • The self rising flour in the recipe can be replaced by 2 1/4 cups cake flour + 2 1/4 teaspoons baking powder. This will take the total baking powder in the recipe to 3 1/4 teaspoons. 
  • I used light brown sugar instead of fine granulated white sugar and the flavor was even better.
  • The sunflower oil may be replaced with extra virgin olive oil.
  • The fresh cream in the frosting may be replaced by Nestle Dessert cream. 


Calories: 471kcalCarbohydrates: 50gProtein: 5gFat: 30gSaturated Fat: 16gCholesterol: 91mgSodium: 198mgPotassium: 186mgFiber: 3gSugar: 32gVitamin A: 726IUCalcium: 44mgIron: 1mg

Disclaimer: Nutritional information for the recipe is an approximation and varies according to the ingredients and products used.

Keyword chocolate, easy baking, easy holiday baking
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  • Reply
    December 26, 2020 at 5:54 am

    These look SUPER yummy! Can’t wait to try making them.

  • Reply
    December 25, 2020 at 1:37 am

    This chocolate cake looks delicious! I will definitely try this recipe once I have all the ingredients at home.

  • Reply
    Krysten Quiles
    December 24, 2020 at 9:44 pm

    I want that in my belly ASAP. That looks absolutely DELISH!

  • 4.46 from 11 votes (9 ratings without comment)

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