Step 1Heat the oven to 350 degrees. Grease 2 (9x5-inch) loaf pans and set aside.
Step 2Cream the butter and sugar in a large mixing bowl.
Step 3Beat the egg yolks then beat into the butter and sugar with the nutmeg, wine and rosewater. Stir in the flour.
Step 4Beat the egg whites until moderately stiff, 3 to 5 minutes, and fold into the mixture. Divide the batter between the loaf pans and smooth the tops.
Step 5Bake the loaves until light brown and a toothpick inserted in the middle comes out clean, 1 1/2 hours. Cool the loaves in the pan slightly, then turn out onto wire racks.