Dessert: United States – Chocolate Sheet Cake with Fudge Frosting

Food safety reminder: Follow safe food-handling practices and use a food thermometer to verify safe internal cooking temperatures.

Serving Size: 16

Approximate Time

Prep 15 min

Cook 35 min

Additional 45 min

Total 1 hr 35 min

Ingredients

For the cake:
2 cups (250 g) all-purpose flour
2 cups (400 g) granulated sugar
3 / 4 cup (75 g) unsweetened cocoa powder
1 1 / 2 tsp baking soda
1 tsp baking powder
1 tsp kosher salt
1 cup (240 ml) buttermilk, room temperature
1 cup (240 ml) hot brewed coffee or hot water
1 / 2 cup (120 ml) vegetable or canola oil
2 large eggs
2 tsp vanilla extract
For the fudge frosting:
1 / 2 cup (1 stick / 115 g) unsalted butter
1 / 2 cup (50 g) unsweetened cocoa powder
1 / 3 cup (80 ml) milk, whole or 2%
3 cups (360 g) powdered sugar, sifted
1 1 / 2 tsp vanilla extract
Pinch fine salt
Optional: 1 / 2 cup (60 g) chopped toasted pecans

Instructions

Preheat oven to 350°F. Grease a 13x9-inch baking pan and line the bottom with parchment for easy release.
Make the cake: In a large bowl whisk flour, sugar, cocoa, baking soda, baking powder, and salt. Add buttermilk, oil, eggs, and vanilla; whisk until mostly smooth. Pour in the hot coffee (or water) and whisk until the batter is thin and fully combined.
Pour batter into the prepared pan and bake 25–30 minutes, until a toothpick inserted in the center comes out with a few moist crumbs.
About 10 minutes before the cake is done, make the frosting: In a medium saucepan over medium heat, melt the butter. Whisk in cocoa and milk; bring just to a gentle simmer, then remove from heat. Immediately whisk in powdered sugar, vanilla, and a pinch of salt until glossy and smooth. Stir in pecans if using.
Finish: Let the cake cool 5 minutes in the pan, then pour the warm frosting over the warm cake and spread to the edges. Let set at room temperature 30–45 minutes.
Slice and serve. Store covered at room temperature up to 2 days, or refrigerate up to 4 days.