Old Fashioned Chocolate Cake

Heat oven to 350 °F (175°C). Grease and flour 13 x 9 x 2-inch baking pan. In a medium bowl, mix together flour, baking powder and salt; set aside. In a small saucepan, combine chocolate and water and cook over low heat, stirring occasionally, until chocolate is melted. Set aside to cool slightly. In a large mixing bowl, beat butter and sugar until light and fluffy; add egg yolks and vanilla and beat well. Add cooled chocolate mixture and beat until blended. Add flour mixture alternately with milk to the butter/chocolate mixture. In a medium bowl, beat egg whites until stiff, but not dry; fold into batter. Pour batter into prepared pan. Bake 45 to 50 minutes or until wooden pick inserted in center comes out clean. Cool completely in pan on wire rack. Frost as desired.