For the Cake: Preheat the oven to 350 degrees. Line a 13 X 18 inch rimmed baking sheet with parchment paper. In a large bowl, mix the flour, sugar, baking soda, and salt together.
Set a small saucepot over medium heat. Add the coffee, butter, and cocoa powder. Whisk well and bring to a boil. Once boiling, whisk and boil for 30-60 seconds. Then remove from heat.
Pour the cocoa mixture into the flour mixture. Whisk well. Then whisk in the buttermilk, eggs, and vanilla, until very smooth.
Pour the batter into the prepared pan. Bake for 20-25 minutes, until the center is puffed and set.
For the Icing: While the cake is baking, place the chopped pecans in a medium saucepot. Set over medium heat. Toast the pecans, tossing every few minutes, until you can smell the pecans toasting.
Then add the butter, buttermilk, and cocoa powder. Whisk well and melt. Once the butter has melted and the mixture is smooth, add the vanilla, and whisk in the powdered sugar, a little at a time. Make sure the only clumps left are the pecans. Keep warm.
Once the cake comes out of the oven, pour the hot icing over the cake, and quickly smooth it over the entire surface of the cake. (It’s ok if the cake is very warm.)
Let the cake cool and the icing set, 30+ minutes. Then cut and serve. (35 small pieces or 24 large pieces)
Video
Notes
Oh Nuts! Pecans are traditional, because they are native to Texas. However, you can use walnuts, almonds, cashews, or even macadamia nuts.If you have a nut allergy, simply omit them.