Ingredients
Method
Instructions
- Preheat your oven to 350°F (175°C). Grease and flour a 15x10-inch jelly roll pan or a 9x13-inch baking pan. In a large mixing bowl, whisk together flour, sugar, baking soda, and salt.
- In a medium saucepan, combine butter, water, and cocoa powder. Bring to a boil, stirring constantly. Once boiling, remove from heat and let it cool slightly before adding to the dry ingredients.
- In a separate bowl, whisk together eggs, buttermilk, and vanilla extract. Pour the hot chocolate mixture into the dry ingredients and mix well. Then add the egg mixture and stir until smooth.
- Pour the batter into your prepared pan and spread evenly. Bake for 18-22 minutes (for jelly roll pan) or 25-30 minutes (for 9x13 pan) until a toothpick inserted in the center comes out clean.
- While the cake bakes, prepare the frosting. In a saucepan, combine butter, cocoa powder, and milk. Bring to a boil, then remove from heat. Whisk in powdered sugar and vanilla until smooth. Stir in nuts if using.
- Pour the warm frosting over the hot cake immediately after it comes out of the oven. Spread evenly with a spatula. Let the cake cool completely before cutting into squares.
Notes
For best results, ensure your eggs and buttermilk are at room temperature. Don't overmix the batter once wet and dry ingredients are combined. Pour warm frosting over warm cake so it soaks in slightly. A larger jelly roll pan makes thinner slices perfect for parties.