This easy chocolate fudge frosting is great for layer cakes and birthday cakes for adults and kids because it's not too sweet, yet not too bitter!
What's in it
Most chocolate fudge frostings are made from cocoa powder, icing sugar, and butter, but for this recipe, we are also using dark chocolate and sour cream, which add depth of flavour and a little acidity to balance out the sweetness of the icing sugar.
If you don't like a chocolate frosting that is too cloyingly sweet, this one is for you.
How it's made
This frosting is made using the creaming method, where the ingredients are whipped together into a smooth, creamy, spreadable frosting for cakes.
This is a good chocolate frosting recipe for beginner bakers, unlike a whipped ganache frosting, because it's less prone to curdling or breaking. Plus, with ganaches and whipped ganache, temperature can be an issue and there is a window where if your frosting is too warm, it will be too thin, but if it's too cold, and you will have trouble icing your cake with it. Chocolate fudge frosting is more forgiving.
For this recipe, the dark chocolate is melted with the butter until it's creamy, glossy, and smooth. This makes it easier to incorporate with the icing sugar and the other ingredients, without the risk of the frosting curdling or breaking from temperature issues where the chocolate is warmer than the other components.
Balancing the flavours
In this frosting, you'll notice there's sour cream in the ingredient list. This contributes a tangy flavour that isn't very noticeable, but it helps to balance out the sweetness of the frosting, so that the chocolate frosting isn't just sugary.
Sour cream provides an acidity here that is hard to beat with any other ingredients. That acidity is what makes some canned frosting so addictive, actually! Remember, the frosting for Christina Tosi's Milk Bar birthday cake is made with citric acid powder, not so much that the frosting is sour, but just enough to brighten it, adding a complexity to the flavour that you might not expect.
Enhancing the chocolate flavour
This chocolate fudge frosting relies on two sources of chocolate for flavour: melted dark chocolate (70 %) and cocoa powder. Using these two together leads to a rich, full-bodied frosting that has more depth than most. As always, make sure to use the best chocolate for baking that you can.
I always bake with cocoa powder that is Dutch-processed, providing more flavour than regular cocoa powder could, and a darker colour.
Not all chocolate is created equal and some brands include a lot of sugar in dark chocolate. Make sure to use the best chocolate for baking. In this case, reach for a bittersweet chocolate that is around 70 % cocoa solids and not too sugary. This is especially important here because you will be adding a lot of icing sugar to make the frosting thick and pipeable, so you don't want the chocolate to contribute even more!
Remember that a great way of enhancing the chocolate flavour in baked goods is to incorporate a little coffee. You can use espresso powder, for example, which will contribute bitter notes to help balance out the sweetness of the frosting, without overpowering the chocolate flavour from the melted chocolate and the cocoa.
A little goes a long way and all you would need to add in this recipe is 5 mL (1 teaspoon), undissolved, along with the icing sugar.
Frequently asked questions
Once the powdered sugar is mixed in, it's hard to adjust the sweetness. You can't take it back. That being said, this frosting should not be overly sweet given that it is made with bittersweet chocolate. If you made it with a sweeter chocolate like a semi-sweet or milk chocolate, expect it to be sweeter.
Try adding a little espresso powder to the frosting to add a little bitterness, which may balance the sweetness. Also a pinch of salt can do wonders in sweet frostings!
I do not suggest substituting any other type of sugar in this frosting recipe. The smooth texture of cream cheese frosting has as much to do with the butter and cream cheese as it does the icing sugar. You can't replace it here with anything else. This is not a baking substitution that I would recommend.
If your chocolate and butter are still warm, the consistency may be on the softer side. If that's the case, put the mixer bowl in the fridge and let it chill for about 20 minutes, then mix it again. Chilling will firm up the chocolate and the butter, leading to a thicker, more sturdy texture that you can pipe and that will hold its shape.
If your frosting is very stiff or seems dry, check the temperature. If you took it out of the fridge, it might need to warm up a little. Some pastry chefs will gently warm a frosting by applying heat to the outside of the metal bowl of the frosting with a hair dryer. Once a thin layer of frosting has warmed a little, you can then try whipping it.
In general, make sure to let your frosting come to room temperature before you try spreading it on your cakes, or you risk tearing the cake with the stiff, cold frosting. It will be a struggle to use!
If your frosting is room temperature and still too dry, make sure you measured out the icing sugar properly. It's possible you made a measurement error, which means, you may have to adjust with more butter and more melted chocolate.... Freshly made, this frosting should really be smooth and creamy, not stiff, nor dry.
Once the frosting is whipped into a creamy, smooth spreadable consistency, you can use it right away or store it in the refrigerator for later. If you will be putting it in the fridge, make sure to cover it tightly with plastic wrap to prevent it from drying or crusting on the surface.
When you are ready to use it, you will need to let it warm up to room temperature before whipping it again. Otherwise if it's too cold, you will have trouble spreading it and it may tear cake layers if you try, leading to a crumby finish that is less professional.
This chocolate fudge frosting is great with banana cake, like in this coffee banana cake where I used a dark milk chocolate, and it's obviously perfect sandwiched between layers of vanilla cake for the classic birthday cake. Of course, it would also work perfectly with this eggless chocolate cake, or in this chocolate caramel cake.
- Melt the butter and the chopped chocolate together in a small bowl over a double boiler. When completely melted and uniform, set aside to cool to room temperature.
- In the bowl of an electric mixer fitted with the paddle attachment, beat together (starting on low) the cocoa powder, vanilla, half the icing sugar, a generous pinch of salt, the cooled melted chocolate mixture, and the sour cream. When the mixture is smooth, add the rest of the icing sugar, and continue beating til it’s smooth and fluffy.
- Make sure to use 70 % dark chocolate or another bittersweet chocolate. If the chocolate is too sweet, the frosting will be sweeter, obviously.
- Calories calculated based on 1 tablespoon (15 mL) serving of frosting