Dissolve sugar and yeast in milk. Stir in 1 1/2 cups all-purpose flour. Cover mixing bowl and allow to rise about 2 hours.
In separate bowl beat 3 egg yolks and 2 tablespoons melted butter. Stir 1/2 cup flour and 1 teaspoon salt into egg mixture; stir well into sponge. Allow batter to rise another 2 hours or until doubled.
Beat to stiff peaks 3 egg whites and fold them into batter; rest 15 minutes.
Cook individual cakes (a few tablespoons each) on hot greased griddle as you would pancakes. Cakes will raise quite high. Top with sour cream, caviar, gravlax, and chives.