Prepare the blini batter by sifting together the flours, salt and baking powder into a large mixing bowl.
Sprinkle the yeast on top, then combine the crème fraîche and milk in a saucepan and heat together very gently. Remove from the heat and whisk in the egg yolks until smooth.
Pour on top of the flour mixture and whisk until smooth and set to one side. Whip the cream in a clean mixing bowl with the lemon essence until soft peaks form. Transfer to a piping bag fitted with a star nozzle and chill until needed.
Melt the butter in a saucepan and transfer to a cup. Brush a blini pan using kitchen paper dipping in the melted butter and heat over a medium heat until hot. Spoon a tablespoon of the batter into the pan and cook the blinis for barely 1 minute, then flip and cook the other side for 30 seconds.
Transfer to a plate, cover with aluminium foil and keep in a warm place until ready to serve. Repeat the process to cook the blinis, remembering to brush the pan with a little melted butter between blinis.
Arrange 4 blinis on each serving plate and top with a folded slice of smoked salmon.
Pipe a little of the cream next to them and garnish with a few slices of spring onion. Garnish with pepper before serving.
For more Canapé recipes