It's daring to declare something as being the ultimate, but I'm confident in my statement. Creamy chocolate icing is poured over warm chocolate cake creating a thin layer of fudge where they both meet. It’s heaven on a plate.
In a 4 quart saucepan over medium low heat, mix together butter, sugar, cocoa, and coffee until just butter is melted and everything is blended. Remove from heat. You don't want to get it too hot as we want to cool it down enough to add the eggs.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt and set aside.
Grease 9x13 baking dish and set aside.
Whisk milk, oil, and vanilla into the chocolate mixture. Mixture should be cool enough to whisk in eggs. Check before adding as we don't want to scramble eggs.
Add the flour mixture into the chocolate mixture. When it is mostly incorporated, whisk an additional 50 - 60 strokes. It should be smooth and blended with no streaks of flour.
Pour batter into pan. Place in oven and bake on the middle rack of oven until toothpick inserted in center comes out clean, about 30 - 35 minutes. Set on rack and begin to make icing.
To make icing:
In a 2 quart saucepan, over medium low heat, combine butter, cocoa, and milk. Whisk until butter has melted and mixture is smooth and bubbling around edges. Remove from heat and whisk in vanilla, salt, and powdered sugar until smooth.
When icing is smooth, pour over warm cake trying to coat the entire surface. The warm cake should help spread the frosting. Spread frosting to cover any bare areas.
Let cool before serving.
Note: If you want to halve the recipe, use a 8x8 square baking pan. It still took 33 minutes in the oven, but please check after 25 minutes in your oven and adjust time from there.*How you measure the powdered sugar determines how your frosting turns out. If you weigh the powdered sugar, it will come out thicker allowing you to spread like traditional frosting. If you measure, then the consistency will be thinner unless you press down and pack the sugar in the measuring cup. Just be warned when you pack it down it will create a poof of sugar dust. This is one time you don’t have to be exact. I have made it both ways and they are both delicious. You can thicken the icing with more powdered sugar or thin with a little more milk.**Lightly sprinkle top with a little sea salt or kosher salt for a delicious burst of flavor.