Chocolate Sheet Cake with Ganache Frosting

A simple, moist and fluffy chocolate cake, topped with the easiest silky frosting ever? Sounds like heaven to me. This chocolate sheet cake with ganache frosting is the perfect treat to make you feel like a pro-baker, even if you just graduated from cake mixes.

I don’t know about you, but I take chocolate cake very very seriously. A dry, flavorless one is a severe crime in my eyes. This recipe had to be absolutely perfect before it even saw the light of day on this blog!

My mission? To create a cake that was flavorful, fluffy, and moist. It doesn’t rely on a heavy frosting to be tasty. It is complemented by a silky ganache that makes it even better!

The first batch was dry and bland, with the next few batches more like a brownie than a cake. But I persevered, and in front of you today is the perfect, easy-to-make, one-layer chocolate cake! Cue the confetti, please.

With Valentine’s Day right around the corner, what better way to celebrate than with the most romantic of flavors: chocolate?

And if it’s just you this V-Day whip it up for yourself and relish in the fact that you don’t have to share it. You can eat the whole thing, like I almost did!

Of course, this simple cake can also be made for birthdays, graduations, anniversaries, or just whenever the need for cake strikes.

But it doesn’t have to be hard to make a delicious dessert from scratch, right at home. Today I’m sharing not only this recipe, but the best tips on how to prevent a baking disaster and how to make the perfect chocolate ganache!

Ingredients for chocolate sheet cake with ganache frosting

You know we like to keep things approachable around here, so of course, we’re working with a very basic ingredients list:

• All-purpose flour: Gives the cake structure, and is the best flour for using with cocoa powder
• Unsweetened cocoa powder: For chocolate flavor, we’re using basic unsweetened cocoa powder, not Dutch-processed. My absolute favorite is Ghirardelli’s, but I’ve heard great things about Hershey’s, as well.
• Instant coffee powder: Enhances the chocolate flavor, so don’t skip. Use a strong, good-quality kind. I am, of course, partial to Blue Mountain’s Jamaican coffee powder.
• Baking soda: For leavening and to balance out the acidity of the cocoa powder and other acidic ingredients that we’ll use.
• Fine sea salt: A small amount of salt to balance sweetness is always used in baking.
• Granulated sugar: I like plain white granulated sugar in this recipe.
• Sour cream: Full-fat sour cream for moisture.
• Vegetable oil: Because oil makes cakes much more moister than butter. Don’t worry, you won’t even miss the butter in this cake. Plus, you don’t have to pull out the stand mixer!
• Buttermilk: For tang and to help us achieve that soft texture. Use full-fat buttermilk; I do not recommend substituting with whole milk or plant milk.
• Eggs: We’ll need just two large eggs for this cake.
• Boiling hot water: An important ingredient to “bloom” the chocolate, explained more a little below.

How to make a simple chocolate cake from scratch

You’ll use the basic cake-mixing method to make this cake: dry ingredients in one bowl, liquids in another, combine, mix, then bake.

1. As always, we start by pre-heating the oven, and preparing our baking pan. Always do these steps first, lest you want to bake in a cold oven or end up with a stuck cake.
2. Gather your ingredients, both dry and wet. It’s always best to let ingredients like eggs, sour cream, and milk come to room temperature before use. To do this, simply take them out of the fridge for at least an hour before you start baking.
3. Take a large mixing bowl and a medium-sized mixing bowl. In the large one, add all the dry ingredients (including sugar) and give it a good whisk to combine everything. Combine the wet ingredients (excluding the hot water, we save that for last) in the medium bowl, mixing them together until smooth.
4. Now, pour the wet ingredients into the bowl with the dry ingredients. Take a rubber spatula, and fold the liquids in very gently until just combined, meaning no large streaks or clumps of flour. This step is done gently and with caution because over-mixing leads to too much gluten development, which leads to a gummy, dense cake.
5. Now it’s time for the boiling hot water. Pour it into your cake batter, then use that same spatula to stir. It will look a little weird (and kind of gross) at first, but as you stir, the batter will become thinner, smoother, and be a rich brown color.
6. Bake in the preheated oven until a toothpick inserted in the center comes out mostly clean (a few tiny crumbs are okay).

Why add boiling water to chocolate cake

The BIG question: why hot water? Won’t it make the batter taste bland? Or scramble the eggs?

All valid questions! We add boiling water to chocolate cake batter to make it “bloom”. The liquid smooths out any lumps and enhances the chocolate flavor of the cocoa powder. Basically, blooming brings out the best in your cocoa powder.

Cake troubleshooting: common issues

Cake-baking, like all baking, is a simple science, but let’s go over some common issues we might run into and how to avoid them:

Q: Why is my cake dense?

A: A few things cause dense cakes. One is too much flour, so be sure you are measuring your flour correctly by using either a kitchen scale or the scoop and level method. Never dunk your measuring cup directly into a bag of flour. You should also be sure to use a good-quality leavening agent (NOT the baking soda that’s been in the pantry for years) and avoid over-mixing the batter.

Q: How to prevent cake from sticking to the pan?

A: This one is easy: prep your pan by greasing it with butter and lining it with parchment paper. Do this step FIRST, because it’s easy to forget when you’re already halfway through making your batter!

Q: Why is my cake wet in the middle?

A: You took your cake out before it was completely finished! To properly check doneness, insert a toothpick in the center of your cake; if it comes out clean (a few tiny crumbs are okay), then it’s done. If wet batter sticks to the toothpick, it needs to bake a little more.

Q: Why is my cake dry?

A: This is often the result of over-baking. Every oven is different, so the time a recipe calls for (yes, even this recipe) can be a little off, depending on how your oven is. I always check my cakes around 5-7 minutes before the finish time stated in the recipe.

How to make perfect chocolate ganache

A ganache is just two ingredients: baking chocolate and heavy cream. It’s basic, but makes a great frosting for cakes:

1. Chop a bar of bittersweet or semisweet chocolate into very fine pieces. Place in a heat proof bowl. Bring heavy cream to a gentle simmer on medium heat. You don’t want the cream to boil; it just needs to be hot enough to melt the chocolate.
2. When you finish heating the cream, pour it into the bowl with the chocolate, and let it sit for about 2 minutes. Stir slowly with a rubber spatula until the chocolate is completely melted into the cream. It will be shiny with a rich color.

To ensure a silky ganache every time, be sure to use a chocolate bar (avoid chocolate chips). Chop the chocolate finely enough, and avoid over-heating the heavy cream.

If you want your ganache to be spreadable like a frosting, make it before the cake so it has enough time to set up. But if you like something thin to use more like a drizzle, feel free to make the ganache after the cake has cooled.

Whewww, that was a lot of info!

I hope I’ve given you all the tools to confidently make this chocolate sheet cake with ganache frosting.

You know I love to see your creations, so be sure to tag #samarafromscratch on Instagram. Be sure to also leave a review or comment.

See y’all later, gonna go eat more cake 🙂