01 -
Preheat oven to 350°F (175°C). Grease a large sheet pan.
02 -
In a saucepan, melt butter, add water and cocoa powder, then bring to a boil. Remove from heat.
03 -
In a bowl, whisk together flour, sugar, baking soda, and salt. Pour in the cocoa mixture and stir.
04 -
Add eggs, buttermilk, and vanilla extract, mixing until smooth.
05 -
Pour the batter into the sheet pan and bake for 20-25 minutes.
06 -
For frosting, melt butter in a saucepan, mix in cocoa powder, and add milk, powdered sugar, and vanilla extract. Stir until smooth.
07 -
Pour warm frosting over the hot cake and spread evenly. Top with chopped pecans if using.