Combine yeast, sugar, and water, and let stand until yeast is foamy. Melt butter in a small skillet over low heat and add shallots or green onion and garlic mixture. Add a bit more butter if necessary, and stir in curry powder. Turn off heat and let mixture stand for 5 minutes. Combine 2-½ cups flour, the curry mixture, 1 teaspoon salt, mustard, and the yeast mixture, and beat for 5 minutes. Cover bowl and let rest for half an hour.

Turn out dough on a floured work surface and knead in remaining flour to make a soft, pliable dough, adding more all-purpose flour if needed. Knead about 10 minutes. Place in oiled bowl and let rise, covered, until doubled; punch down and let rise again until doubled. Turn out dough on a floured work surface and divide dough in half. Roll out each half into a rectangle and roll up into an oblong loaf, pinching ends and seam tightly. Place seam-side down on a cookie sheet sprinkled liberally with cornmeal. Cover loaves lightly with a damp cloth and let stand in a warm place until almost doubled about 45 minutes.

Slash tops of loaves with a sharp knife or razor. Beat egg with ½ teaspoon salt and brush over loaves, being careful not to drip glaze onto pan. Bake in 425 degrees F oven until loaves are golden brown and sound hollow when tapped on the bottom about 25 minutes. Cool on racks before slicing.