Preheat oven to 350° F.
Sift first 6 ingredients together in large bowl. Add eggs, coffee, milk, vegetable oil and the 2 tsp vanilla extract; blend until smooth. Pour thin batter into a greased 13 x 9-inch baking pan. Bake for 35 minutes.
Meanwhile, cream butter until soft and sir in confectioners' sugar, the 1/8 tsp salt, the 3 Tbsp milk, and the 1 tsp vanilla extract. Beat until smooth and creamy adding more milk, if necessary. Spread over warm cake.Makes 4 Source: