Six-Layer Dark Chocolate Cake with Chocolate Buttercream



I made this cake a couple of times previously, and twice over the weekend - one with strawberry SMBC and today, with chocolate SMBC. I did not get to taste the strawberry version but the chocolate was seriously delicious. I love that the dark chocolate in the frosting came out so rich and it did not taste buttery at all.

This is a super easy one bowl chocolate cake that is nearly impossible to screw up, unless you add too much salt like I once did. If you're not as forgetful as me you'll be fine. There's no risk of over-beating, under-mixing, etc. Swiss Meringue Buttercream used to be a complete mystery to me, but it is really easy to make and holds up great once you learn how to. Sweetapolita has a wonderful guide with step-by-step pitcures, be sure to check it out if you're new to making SMBC!

My SMBC usually whips up pretty well despite this hot and humid weather, but with the addition of the chocolate today, it was unusually soft. In my haste to complete the cake, I must have added the still-warm chocolate into the SMBC. So, please do not make the same mistake as me. If you did, however, do that, don't worry, it's not the end. Simply chuck the entire bowl into the refrigerator for about 20-30 minutes, and mix it again using your paddle attachment (or hand mixer) till it comes back to its satiny texture.

Dark Chocolate Cake with Chocolate Buttercream

Yields: 1 6-inch cake about 5" high after torting, filling and frosting
For the Chocolate Cake:
180g (1-1/2 cups) all purpose flour
225g (1 cup) castor sugar
60g (1/2 cup) dark cocoa powder
1-1/4 tsp (6 g) baking soda
1-1/4 tsp (6 g) baking powder
1 tsp (5 g) salt
140ml (5 liquid oz) buttermilk
130ml (4.5 liquid oz) espresso or strong, hot brewed coffee
75ml vegetable oil
2 eggs, at room temperature, lightly beaten
1 tbsp (15 ml) pure vanilla extract

For the Chocolate Swiss Meringue Buttercream:
150g fresh egg whites, about 5 eggs
250g (1-1/4 cups) caster sugar
340g (1-1/2 cups/ 3 sticks) butter, cut into cubes and cool, but not cold*
2 tsp (10 ml) pure vanilla extract
Pinch of salt
300g (1-1/2 cups before melting) melted bittersweet high quality chocolate, cooled

Print this recipe
For the Chocolate Cake:
Preheat oven to 180°C (350° F). Prepare three 6-inch round cake pans with parchment paper rounds, butter/ pan spray and flour or cocoa powder. Tap out excess.

In the bowl of your electric mixer, sift all dry ingredients.

Add all remaining ingredients to the bowl with the dry ingredients and with paddle attachment on mixer, mix for 2 minutes on medium speed (you may need the plastic splash-guard that comes with mixer) and pour into prepared pans. If possible, use a digital kitchen scale and weigh pans for even layers. Batter will be liquidy.

Bake for 20 minutes and rotate pans in oven. Cakes are done when toothpick or skewer comes out with a few crumbs, about 25-27 minutes total. Try not to over-bake. Cool on wire racks for 20 minutes then gently invert onto racks until completely cool.

For the Chocolate Swiss Meringue Buttercream:
Melt chocolate in a bain marie (i use a heat-proof glass bowl over a small saucepan) and set aside to cool.*

Wipe the bowl of an electric mixer with paper towel and lemon juice, to remove any trace of grease. Add egg whites and sugar, and simmer over a pot of water (not boiling), whisking constantly but gently, until temperature reaches 71°C (160°F), or if you don't have a candy thermometer, whisk until the sugar has completely dissolved and the egg whites are hot*.

With the whisk attachment of your mixer, begin to whip until the meringue is thick, glossy, and the bottom of the bowl feels neutral to the touch (this can take up to 10 minutes or so). *Don't begin adding butter until the bottom of the bowl feels neutral, and not warm.

Switch over to paddle attachment and, with mixer on low speed, add butter cubes, one at a time, until incorporated, and mix until it has reached a silky smooth texture (if curdles, keep mixing and it will come back to smooth). *If the mixture is too runny, refrigerate for about 15 minutes and continue mixing with paddle attachment until it comes together. Add vanilla and salt, continuing to beat on low speed until well combined.

Add cooled chocolate, and blend until combined.
Slice the cake layers in half horizontally, using a cake leveler or a large serrated knife and place flat side down on your cake board, pedestal, or plate.

Using a small offset palette knife, spread approximately 1/2 cup of buttercream evenly on the top. Repeat this with remaining cake layers, until you come to the final layer, which you will place with the flat side up.

Place cake on a turntable, and using a offset palette knife, cover the cake in a thin layer of buttercream to seal in crumbs. Refrigerate for 30 minutes (or more). *This does not need to be perfect, as that will come with the top "coat" of buttercream.

Repeat the previous step and for best results, use bench scraper held at 90° against the side of the cake, slowly turning the turntable and keeping your hand steady--let the turntable do the work. Clean up edges with your small offset palette knife.

Chill the cake but bring it to room temperature before serving (about 1 to 2 hours). Be sure to serve Swiss Meringue Buttercream Cakes at room temperature.
I like a little less frosting with my cakes, so i make 3/4 of the SMBC recipe and it's just enough to fill and frost the entire cake.

To test if the egg whites are ready, rub the egg whites/ sugar mixture between your fingers. If it feels gritty, the sugar has not melted yet.

In my hot and humid kitchen, I use the butter almost right out of the refrigerator

You can melt the chocolate in your microwave if you want to, but i prefer the double boiler method as it gives me more control over the heat.

How to Melt Chocolate (Double Boiler Method)
1. Boil about an inch of water in the saucepan.
2. Place the glass bowl with the chocolate (you can use couvertures or chopped chocolate) over the saucepan (be very careful not to let any water get in contact with the chocolate)
3. Using a heat-proof spatula, stir the chocolate until it is completely melted (a few minutues depending on the amount of chocolate)
4. Set aside to cool completely before adding to the SMBC (Important: If you add the warm chocolate to the SMBC, it will melt!)

(Bake & Bait // Recipe from Sweetapolita)

Pardon the poor photo, I made the cake a few hours before I was supposed to meet my friends for the birthday celebration and did not have much time to photograph it, with the melting SMBC and other incidents. If you're a klutz like me, you should never bake anything last minute. Not just once, my fingers found their way into the frosting, I even stuck my entire cake lifter into the cake while putting it into the cake box *faceplam


  1. This looks scrumptious! I've always wanted to make Swiss meringue buttercream, but always been intimidated by how much butter and egg whites are used. But it always looks beautiful.


    1. Thank you! I was apprehensive about making Swiss meringue buttercream at first as well, it just seemed so complicated and troublesome but powdered sugar buttercreams were just not working for me in this weather. Once I started making SMBC, I stopped making those. Please do try it, I'm sure you'll love it as much as I do! I would love to hear about how it turned out for you as well!

  2. That cake looks wonderful! I have one question though: did you use caster sugar or powdered sugar for the SMBC?

    1. Thank you! I used caster sugar for my SMBC. I have not used powdered sugar for CMBC before, not sure if it would turn out the same way.

  3. Spotted this on DessertStalking - beautiful photo!