1 (1/4-oz) package active dry yeast (1 1/4 teaspoons)
1 1/2 tablespoons sugar
1/2 cup sifted all-purpose flour (sift before measuring)
1/2 cup sifted buckwheat flour (sift before measuring)
1/4 teaspoon salt
1 cup whole milk, heated to warm (105–115°F)
1/2 stick (1/4 cup) unsalted butter, melted and cooled
2 large eggs, lightly beaten
Accompaniments: sour cream and caviar
Directions
Preheat oven to 250°F.
Stir together warm water, yeast, and sugar in a bowl and let stand until foamy, about 5 minutes. (If mixture doesn't foam, discard and start over with new yeast.)
Add all-purpose flour, buckwheat flour, and salt, then stir in milk, 3 tablespoons butter, and eggs. Cover bowl with plastic wrap and set in a roasting pan filled with 1 inch of warm water. Let rise in a warm place until dough is increased in volume, has bubbles breaking the surface, and is stringy when scooped, 1 1/2 to 2 hours. Stir batter before using.
Heat a 12-inch nonstick skillet over moderately high heat until hot and brush with some of remaining melted butter (if butter browns immediately, lower heat). Working in batches of 4, spoon 1 tablespoon batter into skillet for each blin, then cook, turning over once, until golden on both sides, about 2 minutes. Transfer to an ovenproof platter and keep blini warm in oven.
