In a small bowl, dissolve yeast and 1 teaspoon sugar in warm water; let stand for 5 minutes. In a large bowl, cream the butter, shortening, salt and remaining sugar until light and fluffy. Add boiling water; cool to 110°-115°. Add eggs and yeast mixture; beat until smooth. Stir in enough flour to form a soft dough.
Turn onto a floured surface; knead until smooth and elastic, about 6-8 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 1 hour.
Punch dough down. Turn onto a lightly floured surface; divide into thirds. Divide each portion into nine pieces; shape into balls. Place in three greased 9-in. round baking pans. Cover and let rise until doubled, about 30 minutes.
Bake at 350° for 20-25 minutes or until golden brown. Cool in pans on wire racks.