In a medium bowl mix buckwheat flour, yeast and salt.
Add warm milk and stir. Cover and set in warm place to rise for 1 hour. (Can be prepared to this point and kept in the fridge over night. Bring to room temperature to continue.)
Stir in the butter, egg yolk and buttermilk.
Whisk egg white to soft peaks and gently fold into batter. Cover and let sit 30 minutes.
Heat a large skillet or pancake griddle over medium heat.
Brush with melted butter. Pour 2-3 tablespoon batter onto griddle or pan depending on the size of pancake you want.
Cook until bubbles form on the surface, about 1 minute. Flip pancakes and cook a little less on the second side.
Remove from pan and keep warm while cooking them all.
Serve warm with lox, (gravlax or smoked salmon), sour cream (or crème fraîche), fresh dill and lemon.
Notes
*Gravlax, lox and smoked salmon are different ways of preserving salmon. Gravlax is cured in a mixture of salt, sugar and dill or other herbs. Lox is cured or brined in salt but is not smoked. Smoked salmon is cured or brined, and then smoked. It is also delicious with blini but the presentation isn't as fancy. Use any of them.**Crème Fraîche Recipe - Stir together 1 cup whipping cream with ½ cup full fat sour cream. Cover and let sit overnight at room temperature to thicken. Stir and store in the fridge.