Single Layer Chocolate Ganache Buttermilk Cake

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This single layer chocolate ganache buttermilk cake is my version of the best chocolate cake! It is every chocolate lovers dream and will brighten up your day in no time. Even though its diameter is small, this is a very thick chocolate cake. I use four different tricks that are known to create the best qualities most seek in a chocolate cake. They each add to the softness, and moistness or enhance the flavor of chocolate in the cake. By far, I’ve never had luck with coming across a recipe that uses all of these tips and tricks. The flavor and texture of this cake is thus unparalleled by any other!

Moist chocolate ganache buttermilk cake shot from the top.

Ingredients you’ll need to make this cake:

All-purpose flour: I highly recommend weighing all your ingredients using a kitchen scale for accurate recipe results. If you’re using cups, don’t scoop your cup into the flour. Spoon the flour into your cup and level it off with the back of a knife.
Cocoa powder: A good quality natural and unsweetened cocoa powder is the best (I use Hersheys and I love it). This can make a huge difference in the taste of chocolate in your baked goods. I highly recommend you use a cocoa powder which is natural and unsweetened.
Espresso powder: Such small quantities of espresso powder in both the cake and ganache will not add any coffee flavor to your cake but rather, it will only enhance the flavor of chocolate in both of them making them even more delicious!
Brown sugar: Brown sugar adds more softness and moisture to your muffins along with also helping the muffins to hold their shape and structure.
Oil: You can use either vegetable oil or canola oil. This is one of the secrets resulting in this cake being ultra soft and moist. Oil reduces the gluten formation in your batter, which makes the cake more moist as compared to using butter as a fat. I do not recommend using olive oil, as it adds a strong flavor of it’s own and changes the taste.
Egg: Use a large egg and bring it to room temperature before mixing in. Eggs strengthen the binding of your cakes and also add moisture. Having your eggs at room temperature makes it easier to incorporate them and allow them to mix thoroughly in your cake batter. A good way of doing this is by letting them sit in a bowl filled with room temperature water for around 10 minutes or until they come down to room temperature.
Vanilla: You must use a high quality pure vanilla extract in your recipes. This helps to add a rich flavor to your baked goods especially when they contain chocolate. Pure vanilla extracts are typically dark brown in color. This enhances the flavor of all ingredients and you should never leave this out.
Buttermilk: Buttermilk is more acidic and has a higher fat content than whole milk too. Both of these things help it cut through the sweetness of the cake, giving it a better flavor overall. It also helps to add moisture to the cake.
Hot water: You will need boiling hot water to be directly added to this cake batter after mixing in all the other ingredients.
Chocolate: I highly recommend using good quality baking chocolate chips or chocolate bars (I use callebaut) to ensure the best flavor. This will also help you get a very silky and shiny chocolate ganache glaze.
Unsalted butter: It is very important to have your butter at room temperature. You can ensure this by lightly pressing your finger on the block of butter. It should slightly leave an imprint. I also prefer to use unsalted butter because salted butters have varying amounts of salt content in them and it is always a good idea to add it on your own and avoid your bakes from being too salty.
Powdered sugar: This will help add sweetness and thicken to your ganache. You should only add a few spoons at a time and mix until completely incorporated and you get the desired consistency. Don’t use granulated sugar as it will not dissolve in your ganache as well as powdered or confectioners’ sugar will.

Very moist chocolate cake topped with a silky ganache frosting

Some Notes:

How is this cake so moist?

This cake is the most moist chocolate cake I’ve ever had. The secret ingredients for that are brown sugar, oil, eggs, buttermilk and boiling hot water. Brown sugar adds more softness and moisture than granulated sugar. Oil reduces the gluten formation in your batter, which makes the cake more moist as compared to using butter as a fat. Eggs strengthen the binding of the cake and add moisture along with contributing to the fat content in the cake. Buttermilk has a higher fat content than whole (full-fat) milk, thus adding moisture to your cake. For hot water, read below!

Why is boiling hot water important to make this cake?

I believe that adding hot water is what makes this recipe so delicious & moist. Hot water is added at the very end of the process. The reason for this is that after all the other ingredients are mixed, the flour is very effectively coated with fat (oil and eggs). Adding water at this point reduces the amount of gluten that can be formed, thus making the cake more moist. The reason the water is hot is because a hot liquid along with espresso powder helps bloom the cocoa powder, creating a deeper, more rich chocolate flavour.

How to avoid dome shaped cakes?

Whether you’re making a layer cake or a single layer cake, flat tops are always desirable. The reason why cakes dome that your cake pan heats up much faster than the rest of the cake causing the edges to set before the cake has risen fully, and as the rest of the cake cooks the centre rises and creates a dome. To avoid this from happening you want to protect the edges of your cake pan. To do this, you can wrap cake strips, foil, or a damp cloth around the edges of your cake pan. Be careful with the damp cloth as it might start burning after it completely dries out. This trick will ensure you get flat tops always!

Can I make cupcakes or a layer cake instead?

Yes you most definitely can. This recipe will yield 12 large cupcakes. If you want to make a layer cake, double or triple the quantity of ganache depending on the way you want to frost it. You can either double this batter and form two very thick cake layers or you can also divide this batter into two 6-inch cake pans. If you want to make a 9-inch cake, this batter will yield one 9-inch cake. You can double it if you want a 9-inch layer cake.

Other Chocolate recipes you’ll love:

One slice of moist chocolate buttermilk cake

Some other tips to make this recipe:

Boiling hot water reduces gluten formation thus making the cake more moist. It also helps enhance the flavor of chocolate in the cake just like espresso powder and vanilla extract.
If you’re in a pinch and don’t have buttermilk in hand, I have a DIY substitute for you. Add 1 teaspoon of lemon juice in half cup. You can double or half this as required. Fill that cup with whole milk to the top. Mix and let it sit for 5 minutes. That’s it, your buttermilk is ready. Your muffins may not turn out marvellous, but they will still be delicious!
I highly recommend investing in an oven thermometer and a kitchen scale. Baking at accurate temperatures and weighing your ingredients correctly ensure that you can replicate the recipes perfectly and enjoy the best flavors.

Happy Baking!