In bowl, dissolve ½ tsp. Of the sugar in warm water. Sprinkle in yeast; let stand until frothy, about 10 minutes. In separate bowl, beat egg, milk and remaining sugar. Add flours and salt; beat for 1 minute. Beat in yeast mixture and half of the butter. Cover with plastic wrap; let rise in warm place until doubled in bulk, about 1 hour.
Heat nonstick skillet over medium heat; brush lightly with some of the remaining butter. Without stirring, spoon batter into pan by scant 2 tablespoonfuls to make a 2 1/4 “ blini. Cook until bubbles form on top that do not fill in, about 1 minute. Turn and cook until bottoms are golden, about 30 seconds. Makes 50 blini