For the cake:
Preheat oven to 350 degrees or 170 degree C.
Grease and flour two or one big round baking pans.
In a large bowl, mix sugar, flour and 1/4 teaspoon salt and baking soda. Set aside.
Melt butter in a pot over medium-low heat.
While that's melting, add 3 tablespoons instant coffee to 1 cup boiling water. Set aside.
Once butter has melted, add coffee mixture to the butter in the pot. Let it come to a boil for about ten seconds, then turn off the heat. Set aside for just a minute.
In a separate bowl, add buttermilk, eggs, and vanilla. Mix until well combined.
Pour the butter/ coffee mixture into the flour mixture. Stir the mixture together gently. The purpose here isn't to mix it together perfectly, but to cool down the heat before adding the egg mixture.
Add in the egg mixture and stir gently until well combined. Then pour into pans. Bake for 20-22 minutes or until cooked. (Chef says: For one big pan took me almost 35-40 minutes.)
Allow to cool completely.
For the mocha frosting:
Combine all icing ingredients. Then ice the cake. Chill for an hour before serving.
(Chef says: I layered my cake. So i had some frosting in the middle and lots around it as well.)