Denver Chocolate Sheet Cake

Classic Fudgy Chocolate Sheet Cake

A timeless dessert that’s as rich in history as it is in flavor. This chocolate sheet cake became a community favorite when it appeared in early Junior League cookbooks—especially the Denver edition. It’s everything you want in a homemade cake: moist, fudgy, and topped with a luscious cocoa frosting. Add some chopped nuts on top for a bit of crunch if you like!

---

🧾 Ingredients

For the Cake

Ingredient	Amount
All-purpose flour	2½ cups (plus extra for dusting)
Granulated sugar	2 cups
Baking soda	1 teaspoon
Salt	¼ teaspoon
Unsalted butter, cubed	2 sticks (plus extra for greasing)
Dutch cocoa powder, sifted	½ cup
Water	1½ cups
Buttermilk	½ cup
Eggs, lightly beaten	2
Vanilla extract	1½ teaspoons

For the Frosting

Ingredient	Amount
Unsalted butter	1 stick
Dutch cocoa powder, sifted	½ cup
Buttermilk	6 tablespoons
Vanilla extract	1 teaspoon
Salt	¼ teaspoon
Powdered sugar	3½ cups
Chopped walnuts or pecans (optional)	½ cup

---

👩‍🍳 Instructions

To Make the Cake:

1. Preheat the Oven
   Set your oven to 350°F (175°C). Grease and flour a 9×13-inch cake pan.
2. Combine Dry Ingredients
   In a large bowl, whisk together the flour, sugar, baking soda, and salt. Set aside.
3. Make Cocoa Mixture
   In a saucepan over medium-low heat, combine the butter, cocoa powder, and water. Stir until the butter is melted and the mixture is smooth.
4. Mix the Batter
   Pour the warm cocoa mixture into the bowl with dry ingredients and stir just until combined. Add buttermilk, eggs, and vanilla extract. Mix gently until smooth and well blended.
5. Bake
   Pour the batter into the prepared pan and bake for 28 to 32 minutes, or until a toothpick inserted in the center comes out clean. Let the cake cool fully in the pan before frosting.

---

To Make the Frosting:

1. Heat and Whisk
   In a small saucepan, melt the butter over medium-low heat. Whisk in the cocoa powder and buttermilk, and cook for about 1 minute until the mixture thickens slightly.
2. Finish the Frosting
   Remove from heat. Stir in vanilla, salt, and powdered sugar, whisking until smooth and glossy.
3. Frost the Cake
   While the frosting is still warm, pour it over the cooled cake and spread it evenly with a spatula. If using, sprinkle chopped nuts over the top.
4. Let It Set
   Allow the frosting to firm up for at least 1 hour before slicing. Cut into 15 squares and serve.