Old-Fashioned Chocolate Sheet Cake is the kind of simple, dependable chocolate cake I like to keep in my back pocket for birthdays, potlucks, and holidays. It bakes in a big pan, slices neatly, and the whole thing has that soft, moist crumb that feels very classic.
My favorite part is the warm cocoa fudge frosting that goes on while the cake is still warm. It sets into a smooth, glossy layer with that old-school cocoa flavor I want in a sheet cake, and it stays pleasantly fudgy instead of turning dry.
I usually serve this as a party sheet cake dessert because it feeds a lot of people without any fuss. It’s also nice with a simple scoop of vanilla ice cream or just a cold glass of milk.
Why You’ll Love This Recipe
Fast and easy: This one comes together quickly and bakes in about 20 minutes, which is exactly what I want from a sheet cake.
Real cocoa flavor: It’s rich and chocolatey in a straightforward way, with cocoa in both the cake and the frosting.
Warm-frosted finish: Pouring the frosting on warm gives you that classic, slightly fudgy top layer that sets up nicely for slicing.
Great for sharing: A 13 x 18 inch pan makes a lot of servings, and it’s easy to transport and serve right from the pan.
Pecan optional: You can keep it smooth, or add chopped pecans for a little crunch and that traditional Texas-style feel.
Ingredients You’ll Need
Cake
- All purpose flour: I use regular flour here, nothing fancy. Spoon and level if you tend to pack your measuring cup.
- Granulated sugar: This is the classic sweetness for this style of sheet cake, and it helps keep the crumb moist.
- Baking soda: Don’t skip it. It reacts with the buttermilk and helps the cake rise evenly in the big pan.
- Fine salt: It makes the chocolate taste more like chocolate. If you only have kosher salt, just keep in mind it measures differently.
- Unsalted butter: Butter gives this cake that old-fashioned richness. If you use salted butter, I’d cut the added salt a bit.
- Water: This helps dissolve the cocoa and makes the batter pourable, which is important for a thin sheet cake.
- Unsweetened cocoa powder: Dutch-process or natural both work here. I use whatever I have, and I keep the same amount either way.
- Buttermilk: This is the tenderness and tang in the cake. If you’re out, the milk-and-vinegar swap works just fine.
- Eggs: Use large eggs. They help the batter turn smooth and glossy and keep the cake from feeling crumbly.
- Vanilla extract: It rounds out the cocoa flavor. I like a real vanilla extract here, but use what you have.
Cocoa Fudge Frosting
- Unsalted butter: This is what makes the frosting taste like fudge instead of a plain cocoa glaze.
- Whole milk: Whole milk gives the frosting a nicer body, but 2% works in a pinch.
- Unsweetened cocoa powder: Same deal as the cake: Dutch-process or natural is fine. Use a cocoa you like the taste of.
- Powdered sugar: Sift it if yours is lumpy. It helps the frosting go smooth fast before it starts setting.
- Vanilla extract: A little vanilla keeps the frosting from tasting flat.
- Fine salt: Just enough to keep the frosting from tasting overly sweet.
- Chopped pecans (optional): I like the crunch, but I leave them out when I want cleaner slices or I’m serving kids.
Recipe Instructions
- Preheat the oven: Heat the oven to 350°F. Grease a 13 x 18 inch rimmed sheet pan, and line it with parchment if you want easier lifting and cleanup.
- Mix the dry ingredients: In a large bowl, whisk the flour, sugar, baking soda, and salt until everything looks evenly mixed.
- Boil the cocoa mixture: In a saucepan, bring the butter, water, and cocoa powder to a boil, stirring so the cocoa dissolves.
- Add the cocoa to the bowl: Pour the hot cocoa mixture over the dry ingredients. Whisk until smooth and you don’t see dry pockets.
- Add the wet ingredients: Whisk in the buttermilk, then whisk in the eggs and vanilla until the batter is fully combined and glossy.
- Bake: Pour the batter into the prepared pan and spread it into an even layer. Bake for about 18 to 22 minutes, until a toothpick comes out clean and the top springs back lightly.
- Make the frosting: During the last 5 minutes of baking, bring the butter, milk, and cocoa powder to a boil. Remove from the heat, then whisk in the powdered sugar, vanilla, and salt until smooth, and stir in the pecans if you’re using them.
- Frost and cool: Pour the warm frosting over the warm cake and spread quickly into an even layer. Cool until the frosting sets, about 30 to 60 minutes, then slice and serve.
Some of my tips!
This is the part that really makes a difference. If you only read one section, make it this one because this is where I share the little trick that helps the recipe turn out so well.
Recipe Tips & Tricks
Don’t overmix once the flour is in. Whisk just until the batter is smooth. Overmixing can make the cake a little tougher, especially around the edges.
Use a true 13 x 18 inch rimmed sheet pan. A smaller pan makes the cake thicker and it won’t bake in the same time range. If your pan is smaller, expect a longer bake and keep an eye on the center.
Work quickly when you spread the frosting. This frosting starts to set as it cools, so I like to have the powdered sugar measured and ready to go.
Pick your cocoa based on the flavor you like. Natural cocoa has a slightly sharper chocolate taste, and Dutch-process is a little smoother. Both work, so I don’t overthink it.
Add mini chocolate chips if you want it richer. Stir them in at the end so they’re evenly distributed. It makes the cake a bit more decadent, but it’s still a sheet cake you can slice and serve easily.
Make some touches!
There are plenty of easy ways to serve this depending on the occasion. Keep it simple, or add a few small touches to make it feel a little more special.
Serving Suggestions
- Milk: A cold glass of milk is classic with this cake. It’s especially nice if you go heavy on the fudge frosting.
- Ice cream: Vanilla ice cream on the side is simple and really good here. I like it best when the cake is at room temp so the frosting stays fudgy.
- Fresh berries: Strawberries or raspberries are easy on the plate and cut through the richness a bit. I’ll do this when I’m serving it after a bigger meal.
- Hot coffee: This is a good cake-and-coffee situation, especially in the afternoon. I usually keep the coffee plain and let the cake be the sweet part.
Save it for later
This section covers how to store leftovers and what parts of the recipe you can prepare ahead of time.
Storage and Make Ahead
Store the cake covered at room temperature for up to 2 days. I usually keep it right in the pan with a tight lid or foil. The frosting keeps the top from drying out much.
Refrigerate leftovers for up to 5 days. The frosting will firm up more in the fridge, which is totally fine. Let slices sit out for a bit if you like a softer texture.
You can make this recipe ahead for parties and potlucks. I like baking it the day before and keeping it covered, then slicing right before serving.
If you want to stretch it longer, you can freeze individual portions wrapped well. Thaw in the fridge overnight, or let a slice sit at room temperature until it softens up.
A few quick answers
This section covers a few extra details that may help before you head to the recipe card.
Recipe FAQs
Can I use Dutch-process cocoa instead of natural cocoa?
Yes. Dutch-process or natural cocoa both work in this recipe, and you can use the same amount. The flavor will be a little different (Dutch-process is usually smoother), but the cake still bakes up well.
What can I use if I don’t have buttermilk?
You can make a quick substitute with milk and vinegar or lemon juice. Mix the milk with vinegar or lemon juice, let it sit for about 5 minutes, then use it as your buttermilk.
How do I know the sheet cake is done?
I look for two things: the top should spring back lightly when you press it, and a toothpick in the center should come out clean. Start checking around 18 minutes since sheet cakes can go from done to overbaked pretty fast.
Do I have to add pecans to the frosting?
No, they’re completely optional. I like pecans for a little texture, but I leave them out when I want the frosting perfectly smooth or I’m serving people who don’t like nuts.
Can I add chocolate chips to the batter?
Yes. Mini chocolate chips are easiest in a thin sheet cake because they distribute better. Stir them in at the end so you don’t overmix the batter.
You might also like
Before you go, take a look at a few other recipes below the recipe card. They use similar ingredients in a different way and are worth saving too.
MORE DINNER RECIPES TO TRY
Old-Fashioned Chocolate Sheet Cake
INGREDIENTS
Cake
- 2 cups all purpose flour
- 2 cups granulated sugar
- 1 tsp baking soda
- 1 tsp fine salt
- 1 cup unsalted butter
- 1 cup water
- ¼ cup unsweetened cocoa powder
- ½ cup buttermilk
- 2 large eggs
- 2 tsp vanilla extract.
Cocoa Fudge Frosting
- ½ cup unsalted butter
- ⅓ cup whole milk
- ¼ cup unsweetened cocoa powder
- 3.5 cups powdered sugar
- 1 tsp vanilla extract
- ¼ tsp fine salt
- ¾ cup chopped pecans optional.
INSTRUCTIONS
Prep
- heat oven to 350 F
- grease a 13 x 18 inch rimmed sheet pan and optionally line with parchment.
Cake Batter
- whisk flour sugar baking soda and salt in a large bowl
- bring butter water and cocoa to a boil in a saucepan then pour over dry ingredients and whisk until smooth
- whisk in buttermilk then eggs and vanilla until fully combined and glossy.
Bake
- pour batter into prepared pan and spread evenly
- bake until a toothpick comes out clean and the top springs back lightly about 18 to 22 minutes.
Frosting and Finish
- during the last 5 minutes of baking bring butter milk and cocoa to a boil then remove from heat
- whisk in powdered sugar vanilla and salt until smooth then stir in pecans if using
- pour warm frosting over warm cake and spread quickly into an even layer
- cool until frosting sets about 30 to 60 minutes then slice and serve.
