Making the batter

1. combine 500 ml (2 cups) warm milk with the yeast; stir well to prevent lumps;
2. combine the flours; add 750 ml (3 cups) flour to the milk; let the batter rest in a warm draft-free place or in a warm turned-off oven for 40 minutes; 
3. beat the egg yolks with the salt, mix them into the batter with the oil and add the rest of the flour little by little. The batter should be slightly elastic; 
4. gradually mix in the remaining warm milk; cover the batter and let rise until doubled in volume; stir and let rise again; 
5. beat the egg whites to stiff peaks; fold into the batter and let rest another 15-20 minutes. 

1. butter the skillet well; 
2. ladle in some of the batter, turning the pan to create an even circle; cook for a few moments like an ordinary pancake; turn and cook the second side; transfer to a plate, keep warm and continue until all the batter is used up. 

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Photo: Russian caviar