Step 1

Preheat oven to 325 degrees F. If not using a nonstick pan, lightly grease (or spray with nonstick spray) a jelly-roll pan that is 15x10 inches.

Step 2

Make the cake. In a large bowl, whisk together flour, granulated sugar, baking soda, and salt until well combined.

Step 3

Stir in buttermilk, eggs, and vanilla until just combined.

Step 4

Meanwhile, melt butter in a small saucepan over medium-high heat. Stir in water, cocoa, and coffee granules. Bring to a boil stirring constantly until smooth. Cool slightly then slowly stir into cake batter.

Step 5

Pour cake batter into prepared pan and bake at 325 degrees F for about 20-25 minutes or until toothpick comes out clean.

Step 6

Make icing. When cake is almost done, start preparing icing by melting butter in small pan over medium-high heat. Stir in buttermilk, cocoa powder, and salt. Bring to a boil while stirring constantly. Slowly stir in powdered sugar and continue stirring until smooth. Remove from heat. Stir in vanilla. Cool slightly but keep warm.

Step 7

Pour warm icing over warm cake (be careful that frosting does not go over edge of pan). Cool cake in fridge or on wire rack for frosting to set.