TVOROZHNAYA BULKA A fluffy, delicate, sweetish bread from the Baltic. 2 packages active dry yeast ½ cup plush 1 teaspoon sugar 1 cup milk, scalded and cooled to lukewarm 3¼ to 4 cups unbleached all-purpose flour 6 tablespoons unsalted butter, at room temperature 2 large eggs ½ pound Friendship brand farmer's cheese 2 tablespoons rum Grated zest of one lemon ½ teaspoon salt 2 tablespoons unsalted butter, melted 1 large egg yolk, beaten with 1 teaspoon milk Confectioners' sugar In a large bowl, combine the yeast, 1 teaspoon sugar, and milk.  Let stand until foamy, about 5 minutes.  Stir in about 2 cups of the flour and beat with a wire whisk until smooth Cover with a linen or cotton kitchen towel and put in a warm place.  Let stand until doubled in bulk, about 1 hour. In a medium-sized bowl with an electric mixer, beat the 6 tablespoons butter and ½ cup sugar until light and fluffy.  Then beat in the eggs, then the farmer's cheese.  Beat in the rum, lemon zest, and salt. Stir the butter mixture into the risen batter.   Gradually stir in another 1¼ cups of the flour, stirring continually, until you have a rather soft dough.  Transfer the dough to a floured surface and knead until smooth and elastic, 5 to 10 minutes, adding enough of the remaining flour to prevent sticking. Shape the dough into a ball and place in a large bowl.   Drizzle with the melted butter and turn to coat.  Cover, and let rise in a warm, draft-free spot, until doubled in bulk, about 1½ hours. Punch the dough down and shape into one oval loaf.   Place the loaf on a buttered baking sheet, cover, and let rise for 30 minutes. Meanwhile, preheat the oven to 350º. Brush the loaf with the egg wash and bake until nicely browned about 50 minutes. Cool on a rack.  Dust the loaf with confectioners' sugar.