This beloved recipe first made its debut in September 2021 and has since been updated with gorgeous new images and enhanced details to bring you the best possible baking experience.

Sometimes, the grandeur of a multi-layered cake, as much as I adore my chocolate orange layer cake, isn’t what you’re craving. For those moments when simplicity and pure indulgence are key, a single-layer snack cake like this **chocolate walnut cake** is an absolute revelation. Leveraging my signature fudgy chocolate sour cream frosting, the very same one that graces my famous Matilda’s chocolate cake, this creation is a true chocolate lover’s paradise. If you’re seeking an even more intense chocolate experience, I highly recommend exploring my triple chocolate layer cake or the delightful chocolate pistachio cake!

This is a wonderfully straightforward, single-layer chocolate cake recipe, making it perfect for those times when your schedule is tight but your desire for homemade deliciousness is strong. The rich, moist cake batter is generously infused with finely chopped walnuts, ensuring a nutty surprise in every bite. To elevate the presentation and crunch, I’ve added even more chopped walnuts sprinkled over the luxurious frosting, creating a harmonious balance of flavors and textures.

Why You’ll Adore This Chocolate Walnut Cake Recipe!

• Effortless Oil-Based Cake: The foundation of this incredible dessert is my simple, oil-based chocolate cake recipe. This ingenious method means there’s absolutely no need for creaming butter, simplifying the process and eliminating the requirement for a stand or hand mixer. The result? An exceptionally moist and tender crumb that’s incredibly easy to achieve.
• Generously Packed with Walnuts: Just before this delightful cake heads into the oven, the rich chocolate batter is carefully folded with a generous amount of finely chopped walnuts. This ensures that every forkful delivers a delightful crunch and a wonderful nutty flavor that perfectly complements the deep chocolate notes.
• Luxuriously Fudgy Chocolate Frosting: Capping off this perfect **chocolate walnut cake** is a super fudgy dark chocolate sour cream buttercream. This frosting is known for its intense chocolate flavor and remarkably smooth texture. A final scattering of chopped walnuts adds both visual appeal and an extra layer of texture. Best of all, this buttercream strikes a perfect balance, being intensely chocolatey without being overly sweet.

Perfecting the Chocolate Walnut Cake: Our Recipe Journey

The dark chocolate cake base for this recipe is an absolute favorite, a true cornerstone in my baking repertoire! It’s renowned for its deep, intense chocolate flavor, which is significantly enhanced by the addition of hot coffee. It’s important to note that the coffee doesn’t impart a distinct coffee taste to the cake; rather, its warmth helps to ‘bloom’ the cocoa powder, unlocking and enriching the chocolate’s natural complexity. This identical, tried-and-true chocolate cake recipe forms the heart of my popular Matilda’s chocolate cake and my indulgent chocolate cake with chocolate cream cheese frosting. For this particular creation, I simply introduced finely chopped walnuts, carefully folded into the batter, to create a delightful texture and nutty depth that makes this **chocolate walnut cake** truly unique.

Essential Ingredients for Your Homemade Chocolate Walnut Cake

• Neutral Oil: Opt for a neutral-flavored oil such as canola, vegetable, or sunflower oil in your cake batter. This is key to achieving an exceptionally moist and tender crumb, and it conveniently bypasses the need for creaming butter, streamlining your baking process.
• Hot Coffee: The hot coffee isn’t merely a liquid; it’s a secret ingredient that works wonders with cocoa powder. When combined, it “blooms” the cocoa, intensifying its flavor and resulting in a cake with a deeper, richer, and more pronounced chocolate taste. Don’t worry, your cake won’t taste like coffee!
• Dutch-Processed Cocoa Powder: We use Dutch-processed cocoa powder in both the cake itself and the decadent frosting. This type of cocoa is less acidic than natural cocoa, providing a darker color and a smoother, milder chocolate flavor that truly shines.
• Buttermilk: The inclusion of buttermilk is crucial for achieving an incredibly moist and tender cake. Its acidity reacts with the baking soda, contributing to the cake’s light texture and delicate crumb.
• Walnuts: These provide a fantastic textural contrast and nutty flavor. While walnuts are traditional, feel free to experiment by swapping them out for finely chopped pecans or hazelnuts if you prefer. A critical tip: ensure you chop them very finely to prevent them from sinking to the bottom of your cake during baking.
• Melted Dark Chocolate: For the frosting, the quality of your dark chocolate truly makes a significant difference. Using a high-quality dark chocolate will yield a richer, more luxurious, and intensely flavored fudgy buttercream.
• Sour Cream: This ingredient is vital for the signature tang and creamy consistency of our dark chocolate sour cream frosting. I strongly advise against substituting sour cream with other ingredients to maintain the frosting’s unique balance and texture.

For complete details on exact ingredients and quantities, please refer to the comprehensive recipe card below.

Easy Step-by-Step Instructions to Bake Your Chocolate Walnut Cake

Creating this delicious chocolate walnut cake is a straightforward and enjoyable process. Follow these simple steps for a perfect bake every time.

Step One: In a large mixing bowl, thoroughly whisk together your granulated sugar and the egg for approximately one minute. Continue until the mixture is well combined and you observe a few light bubbles forming on the surface.

Step Two: To the sugar and egg mixture, add the buttermilk, warm hot coffee, vegetable oil, fragrant vanilla extract, and a pinch of salt. Whisk all these wet ingredients together until they are smoothly incorporated and uniform.

Step Three: Incorporate the Dutch-processed cocoa powder into your wet ingredients, whisking until the mixture is completely smooth and free of any lumps. Next, add the all-purpose flour, baking powder, and baking soda. Gently fold these dry ingredients into the batter until no pockets of dry flour remain, being careful not to overmix.

Step Four: Finally, stir in the finely chopped walnuts into the cake batter. Ensure they are evenly distributed throughout for a delightful crunch in every bite.

Step Five: Pour the prepared cake batter into your greased and parchment-lined 8×8 inch baking pan. Bake in a preheated oven at 350 degrees Fahrenheit (175 degrees Celsius) for 35 to 45 minutes, or until a wooden skewer inserted into the center comes out clean.

Step Six: Once baked, allow the cake to cool in its pan for about 10 minutes. Then, carefully remove it from the pan and transfer it to a wire cooling rack to cool completely before frosting.

Step Seven: While the cake cools, begin preparing the frosting. Melt the dark chocolate in a small, microwave-safe bowl. Heat in short 15-second increments, stirring well after each interval to prevent burning and ensure a smooth, glossy consistency.

Step Eight: In your stand mixer (or using a hand mixer), beat the room temperature unsalted butter and confectioners’ sugar together on low speed until they are just combined. Increase the speed to high and continue beating for 2-3 minutes until the mixture becomes wonderfully light and fluffy.

Step Nine: Add the cocoa powder to the butter mixture and mix on low speed initially to prevent it from flying out of the bowl. Once combined, increase the speed to medium and beat for 1-2 minutes. Finally, pour in the sour cream, melted dark chocolate, and a pinch of salt. Mix once more until the frosting is silky smooth and uniformly colored.

Step Ten: Once your cake is completely cooled, generously spread the rich, fudgy chocolate frosting evenly over the top. For an extra touch of texture and flavor, sprinkle additional chopped walnuts over the frosting. Slice, serve, and savor!

Expert Tips & Tricks for a Flawless Chocolate Walnut Cake

Achieving baking perfection often comes down to a few key techniques. Here are my expert tips to ensure your chocolate walnut cake turns out absolutely spectacular every single time:

• Embrace Your Kitchen Scale: For unparalleled accuracy in baking, I cannot stress enough the importance of using a kitchen weighing scale and measuring your ingredients the metric way. Baking is a science, and precise measurements make a significant difference in the final texture and consistency of your cake.
• Room Temperature Ingredients are a Must: Always ensure that all your ingredients, especially dairy products like buttermilk and sour cream, as well as eggs and butter, are at room temperature before you begin. This allows them to combine more smoothly and evenly, resulting in a perfectly emulsified batter and frosting. Remember to pull them out of the fridge at least an hour before you start baking.
• Finely Chop Those Walnuts: The size of your walnuts is critical! For optimal distribution throughout the cake and to prevent them from sinking to the bottom, make sure your walnuts are very finely chopped. I often use a food processor for a consistent, fine chop, but you can also achieve this by placing them in a large ziplock bag and crushing them with a rolling pin.
• Don’t Overmix the Batter: Once you add the dry ingredients to your wet mixture, mix just until no streaks of flour remain. Overmixing can develop the gluten in the flour too much, leading to a tough and dry cake. A light touch yields a tender crumb.
• Cool Completely Before Frosting: Patience is a virtue when it comes to frosting! Ensure your chocolate walnut cake is entirely cooled to room temperature before applying the frosting. If the cake is even slightly warm, the frosting will melt and slide right off, ruining the beautiful presentation and texture.

Can I substitute the buttermilk in this recipe?

Absolutely! While buttermilk is ideal for its moisture and tenderizing properties, you can substitute it with an equal amount of sour cream or full-fat yogurt. Alternatively, you can easily make your own buttermilk: for every cup of milk (whole milk works best), add 1 tablespoon of white vinegar or lemon juice. Stir it gently, then let it sit for about 5 minutes until it slightly curdles before using.

Can I bake this chocolate walnut cake in a round pan instead of a square one?

Yes, you certainly can! This recipe works beautifully in a 9-inch round cake pan. The baking time should remain approximately the same (35-45 minutes), but always perform the toothpick test to ensure it’s cooked through.

How should I store this chocolate walnut cake, and for how long?

To keep your chocolate walnut cake fresh and delicious, store it tightly wrapped in an airtight container in the refrigerator for up to 5 days. When you’re ready to enjoy a slice, it’s best to let it sit at room temperature for about 15-30 minutes. This allows the fudgy frosting to soften slightly and the cake’s flavors to fully develop, ensuring the best eating experience.

If you’ve made this incredibly delicious chocolate walnut cake, please don’t hesitate to leave a ⭐️ rating and a thoughtful review below! Your feedback is invaluable and helps other bakers discover and enjoy my recipes. I absolutely love seeing your culinary creations, so remember to tag me on Instagram @alpineella when you share your masterpiece! You can also stay connected and find more baking inspiration by following along on Pinterest, Facebook, and TikTok!

Chocolate Walnut Cake

Ella Gilbert

Nutrition Information