Step #1 Grease the bottom of 3 (9") pans or one 9x13 pan.
Step #2 In a microwave proof bowl melt the chocolate & water on high for 1 1/2-2 mins or until chocolate is almost melted, stirring after each min; stir until chocolate is completely melted.
Step #3 Mix flour, baking soda, & salt; set aside.
Step #4 Beat butter & sugar in large bowl with electric mixer till light & fluffy.
Step #5 Add egg yolks, one at a time, beating well after each addition.
Step #6 Stir in chocolate mixture & vanilla.
Step #7 Add flour mixture alternately with buttermilk, beating well after each addition.
Step #8 In another bowl, beat the egg whites until stiff peaks form.
Step #9 Gently stir in theto batter & pour evenly into pans.
Step #10 Bake at 350 degrees for 30 mins or until toothpick comes out clean.
Step #11 Cool for 15 mins & remove this from pans.