Mix the flours. Dissolve the yeast in the milk and stir into the flour with the melted butter, egg yolks and a pinch of salt. If the dough is too thick or too thin, the amount of milk can be varied. Cover the dough and leave to rise in a warm place for approx. 20 minutes.
Beat the egg whites until stiff. Fold into the dough with the grated courgette.
Heat a little clarified butter in a pan. Place a spoonful of dough into the pan and fry on both sides for 1-2 minutes each until golden brown. Drain on kitchen paper. Repeat until all the dough has been used. (Keep the blinis warm in the oven at 80°C if desired. )
Pile the blinis on plates to serve.