High Altitude Texas Sheet Cake
Fudgy High Altitude Texas Sheet Cake with a glossy pour-over frosting, adjusted for baking above 3,500 feet. Quick, crowd-friendly, and foolproof.
Servings: 24 servings
Calories: 300kcal
Ingredients
- 1 cup butter
- 1 cup water
- 5 tbsp cocoa powder
- 2 cups flour PLUS 2 tablespoons
- 2 cups granulated sugar LESS 2 tablespoons
- 1/2 tsp baking soda
- 1½ tsp salt
- 2 lg eggs beaten
- 1 tsp vanilla extract
- 1½ cups buttermilk PLUS 2 tablespoons
Frosting
- 12 tbsp butter
- 4 tbsp cocoa powder
- 6 tbsp milk or cream
- 1 pound powdered sugar 16 oz
- 1 tsp vanilla extract
- 1 cup chopped walnuts optional
Instructions
Make the Chocolate Cake
- Start by preheating your oven to 350°F (175°C). Spray a halfsheet jelly roll pan (13″ x 18″) with nonstick spray. There’s no need to flour the pan.
- Combine the butter, water, and cocoa powder in a medium saucepan over medium heat. Stir until the butter melts and the mix just begins to simmer. Don’t let it come to a full boil—pull the pan off the heat once you see the first bubbles. This gives you the rich chocolate base you’re after.
- Whisk together the flour, sugar, baking soda, and salt in a large bowl. Pour in the hot chocolate mixture and mix until smooth. Add the eggs, vanilla, and buttermilk, then stir until you have a uniform batter with no dry patches.
- Pour the batter into your prepped sheet pan and tip it gently so the batter gets into all the corners for a nice, even layer. Bake for 15 to 20 minutes, checking near the center for doneness—the cake should spring back lightly when touched.
- This cake bakes fast in a shallow pan, so keep an eye on it to prevent overbaking. Once done, place the pan on a cooling rack and let it relax for about 3 minutes before moving on to the frosting stage.
Prepare the Chocolate Frosting
- Begin your frosting as your cake starts to bake. In a saucepan over medium heat, melt the butter, then whisk in the cocoa powder until it’s silky and shiny. Take the pan off the heat, stir in the milk and vanilla, and gradually beat in the powdered sugar until the frosting is smooth.
- It’s best to start making the frosting about 10 minutes into your bake time. That way, you’ll have it ready to pour while the cake is still hot and the frosting can still flow over the top of the cake without setting.
- Immediately pour the warm frosting over the slightly cooled cake and quickly spread it out with an offset spatula. Don’t delay—this frosting sets up in a snap. Top with chopped walnuts, sprinkles, or leave it plain if you prefer.
Notes
- Store leftover cake tightly covered at room temperature for up to 3 days. The frosting helps lock in moisture for a soft crumb.
- For nut allergies, skip the walnuts or swap in chocolate chips or coconut flakes for extra texture.
- If you’re baking at lower altitudes, just reduce the extra flour and buttermilk to the amounts used in standard cake recipes.
- Work quickly when spreading the frosting for that signature shiny finish.
- For a flavor twist, stir a pinch of cinnamon into the batter or add orange zest to the frosting for some zing.