Begin by gently warming half of the milk until lukewarm. Crumble the yeast into the warm milk and stir until fully dissolved. In a large mixing bowl, pour the yeast mixture and sift the buckwheat flour directly into it. Stir thoroughly to combine and set the bowl in a warm, draft-free area, allowing the batter to rest and begin to rise.

Once the mixture starts to puff and show bubbles, gradually incorporate the all-purpose wheat flour and the remaining milk. Stir continuously with a wooden spoon until smooth. Return the bowl to the warm spot to rise again.

Meanwhile, melt the butter until just liquid and let it cool slightly. Separate the eggs, mixing the yolks with the cooled butter, along with the sugar and a pinch of salt. Blend this rich mixture into the dough, stirring gently to preserve the airy texture.

In another bowl, whip the cream until soft peaks form. Separately, whisk the egg whites to stiff peaks. Carefully fold the whipped cream and beaten egg whites into the batter, ensuring the mixture stays light and fluffy. Let the batter rest in a warm place for an additional 15–20 minutes to develop flavor and texture.

Heat a small amount of vegetable oil in a non-stick or well-seasoned skillet over moderate heat. Pour in a ladleful of the batter, swirling the pan swiftly to spread it into a thin, even layer. Cook until the underside turns a delicate golden brown and the surface sets. Flip the pancake carefully and cook the other side until evenly browned. Repeat the process, keeping the cooked pancakes warm.

Serve the pancakes warm, paired elegantly with generous spoonfuls of salmon caviar, dollops of sour cream, and slices of smoked salmon for a luxurious and savory experience.