The Fudgiest One Bowl Chocolate Cake with Chocolate Buttercream

Learn how to make the simplest, fudgiest One Bowl Chocolate Cake (Chocolate Sheet Cake) with Creamy Chocolate Buttercream Frosting that will truly rock your world! This cake can be made dairy free too. 

If you’re looking for a classic chocolate cake, click here for my easy, foolproof Classic Homemade Chocolate Cake recipe.

This Fudgy One Bowl Chocolate Cake has at various times been called “the best chocolate cake ever”, “life changing chocolate cake”, and also “holy f****** chocolate cake” by those who have tried it. It’s easily the best chocolate cake that I’ve ever eaten, and better yet, it’s really easy to make. If ever there was a chocolate cake that you’d want to devour like that kid Bruce from Matilda, this is it!

This fudgy chocolate cake is an easy one bowl chocolate cake, topped with my favorite creamy chocolate buttercream frosting. I’ve always loved a good chocolate cake, and while I’ve made many different versions over the years, this right here is my #1.

If you google best chocolate cake, I will bet you dollars to donuts (and also cake), that the recipe you find is a version of (or the exact same as) the Hershey’s chocolate cake (which I know as Ina Garten’s chocolate cake). This cake is also inspired by that, but with one major difference. This cake is not only chocolatey, soft and super moist, but it’s also incredibly fudgy! It’s got the most addictive balance of soft, light cake and fudgy texture.

The fact that this is such an easy one bowl chocolate cake means that you’ll be making this FAR. TOO. OFTEN! 🙂 Honestly, the hardest part about this cake for me is cutting the parchment paper in the shape of my 9 x 13 inch cake pan. But what’s also really great about this recipe is that you can make this as a chocolate sheet cake (which is how I make it most of the time), OR as a 3 layer cake as well!

What makes this Chocolate Sheet Cake (One bowl Chocolate Cake) so special?

• One bowl baby! First add the dry ingredients, then the wet ingredients, whisk and done.
• Perfectly fudgy chocolate cake. I can’t tell you how much I love the fudge factor in this cake. The not so secret ingredient that makes it so dense and fudgy is CREAM CHEESE (and butter). The result is an almost chocolate brownie-like cake.
• It’s super chocolatey, with a good dose of cocoa powder. The last addition of coffee is also important to make the chocolate flavor stand out more.
• This recipe is for a cake made in a 9 x 13 inch cake pan. BUT, you can EASILY make this cake into an 8 inch or 9 inch cake too (more details below).
• This chocolate cake is also quite versatile. Even when things go a little wrong, it still comes out delicious.

Here are a few more tips on making this one bowl chocolate cake (chocolate sheet cake)

What if I don’t have a 9 x 13 inch pan?

No problemo. Like I mentioned before, you can make this in an 8 inch or 9 inch pan.

You can also make a double layered 8 or 9 inch cake. OR you can DOUBLE the recipe and make a THREE layer 8 or 9 inch cake.

What if I don’t have cream cheese?

Substitute the cream cheese with Greek yogurt or sour cream. This would make it slightly less fudgier, but it’ll still taste amazing.

Can I use oil instead of butter to make this one bowl chocolate cake?

Yes you can, but again, this would make it less fudgy. The milk solids in butter help attain that fudgy texture. But if you want to, you can add oil or melted vegan butter or margarine instead.

Why aren’t you using buttermilk in this chocolate sheet cake?

You CAN use buttermilk in place of the milk here. I prefer to add a little vinegar because it helps bring out the chocolate flavor more AND helps with activating the leavening agents (baking soda, baking powder).

Plus, I’m assuming that most people may not have buttermilk in their fridge, and it just seems pointless to buy a carton of buttermilk just to use 1/2 cup for this recipe.

AND you can substitute the milk to make it dairy free too (more details below).

Do I have to use coffee? Won’t this be a mocha cake instead?

No on both counts. You can use hot water instead of hot coffee if you’d like to. But the coffee doesn’t really add any coffee flavor here unless you use EXTRA STRENGTH coffee. If you use regular strength coffee (or even weak coffee), it will simply enhance the chocolate flavor.

And if you’d like to make this chocolate sheet cake without the caffeine, you can simply use decaffeinated coffee instead.

So should I use hot coffee or hot water? 

The hot liquid makes this cake batter runny. If you use liquid that is not hot, then the cake batter will be thicker.

In my experience, a thicker cake batter results in a cake that rises higher after baking and has a lighter cake crumb. This is likely because of the fact that you have to whisk a thicker cake batter more to mix all the ingredients together, resulting in  more air being incorporated.

But a runnier (warm) cake batter is easier to mix without getting too much air in the batter, resulting in a slightly shorter, and a delightfully fudgier cake crumb!

Does it matter what cocoa powder I use for this one bowl chocolate cake? 

I use Callebaut cocoa powder because it’s my absolute favorite. However, you CAN use a cocoa powder that’s accessible to you, and you can also use Dutch processed or black cocoa for an even darker color.

Please note that 3/4 cup Callebaut cocoa powder is NOT equal to 3/4 cup of Nestle cocoa powder.

3/4 cup Callebaut cocoa powder = 90 g

3/4 cup Nestle cocoa powder = 75 g

And there are similar variations if you use Dutch process cocoa powder.

So for this fudgy chocolate cake recipe, I HIGHLY recommend WEIGHING the ingredients to make sure you get consistently accurate results.

Can I make this one bowl chocolate cake vegan? 

Unfortunately, I haven’t tried to veganize this chocolate sheet cake… yet. BUT I have made it dairy free!

Here are the substitutions to make a dairy free chocolate cake

Instead of regular cream cheese you can use vegan cream cheese like Tofutti.

Instead of regular milk, you can use almond milk, coconut milk, cashew milk or any plant based milk. Just don’t forget the vinegar.

Instead of regular melted butter, use dairy free or vegan butter or margarine to keep the fudgy texture. OR you can use oil too.

Now that you guys know how easy this one bowl chocolate cake recipe is, we need to talk frosting! I love topping this chocolate sheet cake with this dreamy, creamy chocolate buttercream frosting. There’s something irresistible about those swirls of pillowy soft, creamy, fluffy frosting adorning your cake masterpiece. I have also made this cake with a ganache frosting before, which also works really well. But if you’re not a fan of the frosting, you can simply dust the surface with some confectioner’s sugar.

Either way, this fudgy chocolate sheet cake will rock your world!

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