Dissolve the yeast with 15 cl of warmed milk (30°C).Combine all dry ingredients, add the yeast mixture and whisk until smooth. Cover with cling film and rest for 3 hours at room temperature.
Add the cold melted butter and egg yolk.
Whip the egg white to soft peaks and gently fold into the batter mix.
Grease a non-stick pan lightly with oil and sizzle a spoonful for 2-3 minutes before flipping over for another minute.Transfer the blinis onto a kitchen towel and keep them warm.