Preheat the oven to 350ºF. Spray an 8" square baking pan with non-stick spray. Set aside.
In a medium size bowl, whisk together the flour, sugar, cocoa powder, and salt. Set aside.
In a medium size saucepan, combine the butter, coffee, and vanilla extract. Heat over medium-high heat and bring to a boil. Remove from the heat and whisk in the flour mixture until thoroughly combined. Add the yogurt, egg, and baking soda. Whisk again until batter is smooth.
Pour the batter into the prepared pan. Bake for 18-20 or until a toothpick inserted in the center comes out clean.
ICING
When the cake has about 5 minutes remaining to bake, prepare the icing. In a medium size saucepan, combine the butter, milk, and vanilla extract and heat over medium-high heat. Bring to a boil, remove from heat, and whisk in powdered sugar, cocoa powder, and salt until smooth. Stir in the chopped nuts.
When cake is finished, remove it from the oven and immediately pour hot icing over the cake. Gently spread the icing into an even payer over the cake. Sprinkle more chopped pecans on top, if desired. Let the icing set before serving (about 30 minutes). Cake will stay fresh covered tightly at room temperature up to 5 days. Cake freezes well, up to 2 months. Thaw in refrigerator overnight and allow to come to room temperature before serving.
Notes
This recipe doubles easily. Bake in 9x13" or 11x15" baking pan. Increase baking time to 20-22 minutes.Adapted from Brown Eyed Baker
All nutritional values are approximate and provided to the reader as a courtesy. Changing ingredients and/or quantities will alter the estimated nutritional calculations.