This delicious Chocolate Walnut Cake is a mash up of moist chocolate cake with a nice nutty flavor from ground walnuts. It's made in one bowl and topped with the most fluffy and luscious homemade chocolate buttercream frosting. It's also a single layer snack cake, so it's easy as can be and perfect for any occasion - holiday, birthday, or really just about any get-together.
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Ingredients
There really is nothing quite like homemade chocolate cake - and this chocolate walnut cake is made with some relatively simple ingredients:
- All purpose flour: This is my go-to flour always. Standard and easy to work with.
- Granulated sugar: Standard baking white sugar. Both the unsweetened cocoa and the walnuts are on the bitter side, so this balances it out.
- Whole milk: Moisture! Whole milk is preferred as it yields a richer texture and flavor.
- Vegetable oil: Really any neutral oil works - vegetable, canola, etc.
- Eggs: Large eggs are the perfect size. These bind the cake together and gives it moisture.
- Vanilla extract: Just a little goes a long way to add more flavor. You could also use vanilla bean paste.
- Cocoa powder: Natural unsweetened cocoa powder - not dutch processed.
- Baking soda & baking powder: Both of these leavening agents are necessary for the perfect rise.
- Espresso powder: Espresso/coffee both compliments and deepens the rich chocolatey flavor.
- Ground raw walnuts: Regular plain walnuts - not roasted or salted. Use a food processor to pulse the walnuts to get a fine ground texture.
- Hot water: Adding hot water "blooms" the espresso to bring the flavor out.
- Kosher salt: Always, for balance.
For the chocolate buttercream:
- Unsalted butter: Always use unsalted so you can fully control the salt. Room temp is crucial.
- Unsweetened cocoa powder: To bring the chocolate flavor.
- Powdered sugar: Sweetens it up.
- Vanilla extract: For added flavor.
- Whole milk: Used to thin it out a little bit to help it get nice and fluffy.
- Kosher salt: To balance out the sweetness.
Step by step instructions
Follow the steps below to make this easy chocolate walnut cake recipe – full recipe with ingredient quantities is in the recipe card at the end of this post.
PREP: Preheat your oven to 350℉. Get your 8x8 baking pan and spray with non-stick spray, and line with parchment paper.
How to make the chocolate cake
1. Combine the eggs and sugar. In a large mixing bowl, whisk together the large eggs and granulated sugar until light pale yellow.
2. Add the remaining wet ingredients (except the water). To the same bowl, whisk in the vanilla extract, vegetable oil, and whole milk.
3. Add dry ingredients (except flour and walnuts). To the same bowl again, whisk in the unsweetened cocoa powder, baking powder, baking soda, salt, and espresso powder.
4. Add walnuts. Gently whisk in the walnuts.
5. Add flour. Whisk in the flour until just combined, with a few flour streaks showing.
6. Add water. In a steady stream, slowly whisk in the hot water until combined.
7. Bake! Pour the cake batter into your prepared pan and bake at 350℉ for 20-30 minutes until a tester or tooth pick poked into the center of the cake comes out clean.
How to make chocolate buttercream
8. Start making the buttercream. In a stand mixer with the paddle attachment whip the (room temp!!) butter for about 3 minutes.
9. Add cocoa powder, salt, vanilla, and sugar. Add the cocoa powder, salt, vanilla, and powdered sugar. Slowly (so the powdered ingredients don't fly everywhere) mix in until combined - it will be dry.
10. Add the milk. Finish it off with the milk and whip until smooth and fluffy.
11. Frost the cake. Spread on the frosting over the top of the cake and sprinkle with chopped walnuts for an added crunch.
Tips and tricks
- Use a food processor to grind the walnuts.
- Use a stand mixer, hand mixer, or mix by hand. I like to use a stand mixer for ease, but it's not necessary.
- Use raw walnuts. Not roasted, not salted, just regular raw walnuts.
- Use room temperature ingredients. This helps make sure that they all combine together really seamlessly for the best cake. It's especially important for the buttercream because the butter won't whip the same if it's cold. More on why this is important here.
- Don't over mix. I know I mentioned it in the directions, but it's really important to not over mix the cake, it will make it it tough and over work the gluten.
- Test the cake when it's almost done baking. Everyone's oven is different, so to ensure you don't over bake the cake, start checking it at 20 minutes. use a toothpick or cake tester - if it comes out dry with a few crumbles, the cake is ready.
- Test your leavening ingredients. To make sure your leavening ingredients (baking powder / baking soda) are still active, test them! For baking soda, add a bit to a bowl and put in a few drops of an acid (citrus juice, vinegar). If it bubbles, it's active.
- For baking powder, add a bit to a bowl and add a little boiling water. If it bubbles, it's active.
Recipe modifications
- Use milk alternatives such as almond milk or oat milk instead of the whole milk
- Use 2% milk
- Use almonds or pecans instead of walnuts
- Serve with a scoop of vanilla ice cream as opposed to chocolate buttercream frosting
- Use a mild olive oil instead of neutral oil
Storage
Store the cake in an airtight container at room temp for up to 3 days, or in the fridge for up to 5.
You can also freeze this cake - wrap it tightly in plastic wrap and it's good for up to 3 months.
FAQs
If you used the proper amount of baking soda and baking powder, it's most probable that your cake didn't rise because of old leavening ingredients. If these have been open for more than 4-6 months, they need to be replaced.
Espresso and coffee really help bring out and maximize the chocolate flavor in cakes. You don't taste the espresso at all (I personally do not like coffee, but love this cake).
The texture! Chocolate fudge cake has a thicker consistency and usually uses chocolate chips/bar of chocolate in the batter.
Yes! You can easily make this a 8x8 round cake (baking time would be the same), or a loaf cake (baking time would be a bit longer - closer to 40-50 minutes).
Natural / unsweetened cocoa powder is naturally a bit acidic, it's what gives that sharp chocolate flavor. Dutch processed is as it sounds - slightly processed to remove some of the acidity. Thus, it has a smoother more mellow flavor. More on this here.
More cake recipes
📖 Recipe
Chocolate Walnut Cake
Ingredients
For the cake
- 2 large eggs
- 1 cup granulated sugar
- ½ cup whole milk
- ½ cup vegetable oil
- 1 teaspoon vanilla extract
- ½ cup unsweetened cocoa powder
- 1 teaspoon baking powder
- ½ teaspoon baking soda
- ½ teaspoon kosher salt
- ½ teaspoon espresso powder
- ½ cup ground walnuts
- 1 cup all purpose flour
- ½ cup boiling water
For the chocolate buttercream
- ½ cup unsalted butter room temp
- ¼ cup unsweetened cocoa powder
- ½ teaspoon vanilla extract
- ¼ teaspoon kosher salt
- 1 ½ cups powdered sugar more or less to taste
- 2 tablespoon whole milk
Instructions
To make the cake
- Preheat your oven to 350℉ and line and spray a 8x8 baking pan.
- In a large mixing bowl, whisk together the eggs and granulated sugar until light pale yellow.
- To the same bowl, add the whole milk, vegetable oil, and vanilla extract and whisk to combine.
- To the same bowl again, whisk in cocoa powder, baking powder, baking soda, salt, and espresso powder.
- Gently whisk in the ground walnuts.
- Then whisk in the flour until just combined. Do not over mix! It's ok to see a few streaks of flour because you're going to whisk a bit more when adding the water.
- Lastly, in a steady stream, slowly whisk in the boiling water until combined.
- Pour the batter into your prepped 8x8 baking pan and bake at 350℉ for 20-30 minutes until a cake tester or tooth pick comes out clean.
- When the cake is done baking, let it sit in the pan for a few minutes, then transfer to a wire rack to cool to room temp.
To make the chocolate buttercream
- While the cake is baking, in a mixer with a paddle attachment whip the (room temp!!) butter for about 3 minutes.
- Add in the cocoa powder, salt, and vanilla. Whip again until combined, then add in the powdered sugar.
- Once that's combined (it will look dry), add in the milk and whip again until smooth and fluffy - a few more minutes.
To finish the cake
- Once the cake Is at room temp dollop on the frosting and spread it around evenly. Top with chopped walnuts (optional), and serve!
Notes
- Use a food processor to grind the walnuts.
- Use a stand mixer, hand mixer, or mix by hand. I like to use a stand mixer for ease, but it's not necessary.
- Use raw walnuts. Not roasted, not salted, just regular raw walnuts.
- Use room temperature ingredients. This helps make sure that they all combine together really seamlessly for the best cake. It's especially important for the buttercream because the butter won't whip the same if it's cold. More on why this is important here.
- Don't over mix. I know I mentioned it in the directions, but it's really important to not over mix the cake, it will make it it tough and over work the gluten.
- Test the cake when it's almost done baking. Everyone's oven is different, so to ensure you don't over bake the cake, start checking it at 20 minutes. use a toothpick or cake tester - if it comes out dry with a few crumbles, the cake is ready.
- Test your leavening ingredients. To make sure your leavening ingredients (baking powder / baking soda) are still active, test them!
- For baking soda, add a bit to a bowl and put in a few drops of an acid (citrus juice, vinegar). If it bubbles, it's active.
- For baking powder, add a bit to a bowl and add a little boiling water. If it bubbles, it's active.
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