Cream butter and sugar until light and fluffy. Add eggs one at a time, incorporating each egg before adding another.
Heat chocolate and 1/2 cup of coffee together until chocolate is completely dissolved.
Beat chocolate-coffee mixture into butter-sugar mixture.
Sift flour, soda, salt together.
Stir in a little of the flour mixture, alternating with the divided 1/2 cup of coffee until all used up.
Add vinegar and vanilla and beat well.
Divide into three 9” pans.
Then, bake at 325F for 25-30 minutes.
Frosting: * With 1/3 cup heavy whipping cream, add 1 tablespoon of strong coffee, 1 tablespoon of cocoa, and 2 tsp. sugar. * When thoroughly chilled, add 2/3 cups of heavy whipping cream and whip. * Spread between layers and top of cake.