Texas sheet cake is a thin, fudgy chocolate cake baked in a large pan and topped with a warm poured frosting that sets into something between a glaze and a soft fudge layer. It takes 45 minutes start to finish and feeds a crowd without any stacking, layering, or decorating. If you need a reliable chocolate dessert that holds up well over a few days, this is it.
What makes this version work
Two things actually matter here. First, the frosting goes on while the cake is still hot — not warm, hot, straight from the oven. That heat lets the frosting sink just slightly into the surface, which is what gives each slice that dense, fudgy top rather than a separate layer that cracks and slides. Pull the cake and make the frosting simultaneously so there’s no waiting around. Second, buttermilk in the batter does real work: it reacts with the baking soda to keep the crumb tender, and its mild acidity stops the cake from tasting flat or one-note. If you only have whole milk, the cake will still bake fine, but the texture will be a little less soft. Buttermilk is worth buying for this one — and skip the pecans on top, honestly. They soften overnight and don’t add enough to justify the extra cost or the bowl you’ll dirty chopping them.
If something goes sideways
- Frosting seized up before you could spread it: It hardened too fast, usually because it sat off the heat too long. Next time, pour it the moment the cake comes out. If it’s already stiff, set the pan briefly over very low heat and stir until it loosens, then pour immediately.
- Cake is dry or crumbly: It overbaked. These thin cakes go from done to dry quickly — start checking at 20 minutes. The toothpick should come out with just a few moist crumbs, not bone dry.
- Frosting is grainy: The powdered sugar wasn’t fully incorporated, or it was added while the butter mixture was still boiling. Remove the pan from heat completely before whisking in the sugar, and sift it first if your bag has any lumps.
- Batter looks lumpy or broken after adding the buttermilk mixture: Keep stirring. The batter comes together once everything is fully mixed — it doesn’t need to be perfectly smooth before it goes in the pan, just evenly combined.
- Cake stuck to the pan: Grease every corner thoroughly, including the sides. Parchment on the bottom is the safer move if you want clean slices for serving a crowd over multiple days.
Texas Sheet Cake
Ingredients
Cake
- 2 cups all-purpose flour sifted
- 2 cups granulated sugar
- ½ cup unsalted butter cubed
- ½ cup water
- ¼ cup unsweetened cocoa powder quality brand
- ½ cup buttermilk
- 2 large eggs at room temperature
- 1 teaspoon baking soda
- 1 teaspoon vanilla extract
Frosting
- ½ cup unsalted butter cubed
- ¼ cup unsweetened cocoa powder quality brand
- 6 tablespoons milk
- 4 cups powdered sugar sifted
- 1 teaspoon vanilla extract
- ½ cup chopped pecans optional, for garnish
Instructions
- Preheat your oven to 175°C (350°F). Grease a 13x18 inch (33x46 cm) baking pan with butter or line it with parchment paper for easy removal.
- In a large mixing bowl, combine the flour and granulated sugar. Set aside.
- In a medium saucepan over medium heat, melt the butter. Whisk in the water and cocoa powder until smooth. Bring the mixture to a light boil, then pour it over the flour and sugar mixture, stirring to combine.
- In a separate bowl, mix the buttermilk, eggs, baking soda, and vanilla extract. Blend this into the chocolate batter until smooth and evenly mixed.
- Pour the batter into the prepared baking pan and spread it evenly. Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
- While the cake bakes, prepare the frosting. Using the same saucepan, melt the butter over medium heat. Stir in the cocoa powder, then the milk, and bring to a gentle boil, stirring constantly. Remove from heat and gradually whisk in the powdered sugar and vanilla extract until smooth.
- Pour the warm frosting over the cake as soon as it comes out of the oven. The heat helps the frosting to spread evenly and soak slightly into the cake, enhancing its moistness. If desired, sprinkle with chopped pecans for an added crunch.
Notes
Nutrition
Common questions
Can I make this cake a day ahead?
Yes — this cake actually improves overnight. The frosting firms up and the whole thing slices more cleanly after a few hours of rest. Cover the pan tightly with foil or plastic wrap and leave it at room temperature; refrigerating it can dry out the crumb.
Can I bake this in a standard 9×13 pan instead of a sheet pan?
You can, but the cake will be noticeably thicker and will need more time in the oven — start checking around 30 minutes. The texture will be closer to a regular chocolate cake than the thin, fudgy result you get from a sheet pan.
How long does it keep, and what’s the best way to store leftovers?
Stored covered at room temperature, it keeps well for 3 days. After that, individual slices can be wrapped and frozen for up to 2 months — thaw at room temperature for about an hour and the frosting comes back to its original texture.
I don’t have buttermilk. What can I use instead?
Add 1 teaspoon of white vinegar or lemon juice to a half-cup of whole milk, stir, and let it sit for 5 minutes before using. It won’t be identical to real buttermilk, but it gives the baking soda something to react with and keeps the crumb from turning dense.
What to cook next
- Chocolate brownies for another easy pan dessert
- Dark chocolate brownies with espresso and sea salt
- Giant chocolate chip cookie cake for celebrations
- French chocolate mousse if you want something richer and smaller-batch
