Combine first 6 ingredients; sift together 3 times.
Beat egg yolks until thick and lemon colored; add dry ingredients alternately with buttermilk, beginning and ending with dry ingredients. Mix well.
Beat egg whites (at room temperature) until stiff but not dry. Fold egg whites and melted shortening into egg yolk mixture. Spoon batter into a preheated, lightly oiled waffle iron, following manufacturer's directions. Cook 5 minutes or until waffle is brown and crisp. Repeat procedure with remaining batter. Serve warm.