Preheat oven to 350 °F. Grease and flour 8 -inch round baking pans and 3 inch in height. In a medium mixing bowl, combine flour, salt, 1 cup of the sugar, baking powder, cocoa and coffee. Make a well in the center, and pour in oil and hot water.
Using electric mixer with paddle attachment, beat mixture at medium-low speed for 3 minutes. Continue mixing at the same speed, add egg yolks one at a time, blending well after each addition, until thoroughly mixed. Set aside.
In another medium bowl, beat egg whites and cream of tartar with wire beater attachment of electric mixer at medium high speed until frothy. Add the remaining 1/2 cup sugar in four additions, beating until mixture is stiff and glossy.
With rubber spatula, gently fold one fourth of beaten egg whites into batter, scrapping bottom of bowl, until lightly blended. Gently fold about 1 cup of batter into beaten egg white mixture. Repeat until all the batter has been blended into egg white mixture. Pour evenly into prepared pans.
Bake for 20 to 35 minutes, then remove from oven and cool on wire rack. Fill and frost with coffee cream frosting and refrigerate.