In a mixing bowl, sift together flour, sugar, baking powder and salt. Combine buttermilk, baking soda and egg yolks. Mix lightly and add to dry ingredients. Mix until batter is barely smooth. Stir in butter; fold in egg whites. Cook on hot greased pancake griddle, turning once, until pancakes are browned both sides. Serve with bacon curls or grilled ham. Makes 8 pancakes. Formatted by Mary Wilson, BWVB02B. ----