Combine the flours in a mixing bowl and add the egg yolk. Dissolve the yeast in the milk and add it, stirring with a wire whisk. Add salt to taste. Set in a warm place and let stand for about 2 hours, covered with a towel.
When ready to cook, add the cream and chopped dill. Beat the egg white and fold it in. Cook in a crêpe pan as with ordinary crêpes.