Cream butter and add sugar, a little at a time. Cream well; add eggs. Sift flour, salt, soda and cocoa together 3 times. Add coffee with flour mixture to batter, alternating. Then add vinegar and vanilla. Bake in 23 cm layer pan 20 to 35 minutes in 350 degrees oven or in loaf pan about 30 to 40 minutes in 350 degrees oven. ----