Mix the salt, sugar, and grated nutmeg with the flour. Scald the milk and melt the butter in it. Dissolve the yeast in a quarter cupful of lukewarm water. When the scalded milk has become lukewarm, add to it the dissolved yeast and the eggs, which have been well beaten, the yolks and whites separately; then add the flour. Use more flour than given in the receipt, if necessary, but keep the dough as soft as possible. Knead it on a board for twenty minutes. Let it rise over night in a warm place, well covered. In the morning turn it on to the molding-board, roll it and rub it lightly with butter, then fold it several times, cut it into pieces the size of a large egg, and mold it into balls. The folding is to make it peel off in layers when baked, but may be omitted if desired. Press into the side of each bun, after it is molded, a piece of citron and lump of sugar wet with lemon-juice. Place the buns in a baking-tin and let them rise to more than double their size. Brush the tops with egg diluted with water to give a brown crust. Bake in a moderate oven for half an hour. When baked, brush over the tops with sugar dissolved in milk, and return to the oven for a few minutes to glaze. Sprinkle a little powdered sugar over the tops as soon as they are removed from the oven.