Beat the egg and milk together, and stir in the sugar and yeast. Sift the flours and salt into a warm bowl, and whisk in the liquid. Cover the bowl and leave it to stand in a warm place for about 45 minutes, until the mixture has doubled in size.
Heat a heavy-based frying pan or griddle, and wipe it over with a few pieces of kitchen paper dipped in oil. Pour on a ladleful of batter and cook until the surface looks dry, with holes in it. Turn the blin over and cook quickly on the other side. It should not take more than 1–2 minutes for each blin. If you have a very large pan, or can manage two pans, you can cook several blini at a time. Keep them warm on a heatproof plate set over a pan of hot water. Serve each with a spoonful of soured cream and caviar.
© 1995 Frances Bissell. All rights reserved.