For the blinis, separate the eggs. Mix flour and buckwheat flour. Dissolve yeast in milk and stir with melted butter, egg yolks and salt. Mix liquid mixture into flour. If the dough is too thick or thin, add milk or flour to desired consistency. Cover and leave dough for about 20 minutes in a warm place. Whisk egg whites until stiff and fold into the batter before baking.
Heat some butter in a pan, add a tablespoon of dough and toast both sides until golden brown for 1-2 minutes each. Toast all blinis this way. Remove from heat and place on a paper towel. Then add to a preheated 80°C (approximately 175°F) to keep blinis warm.
For the garnish, Rinse lemon in hot water, peel lemon rinse and cut into small pieces. Place a dab of crème fraîche on each blini. Cut the salmon into pieces and drape on the blinis around the crème fraîche. Serve garnished with lemon, dill and caviar.