In a large bowl, dissolve yeast in warm water. Add 1/2 teaspoon sugar; let stand for 5 minutes. Remove seeds from cardamom pods; coarsely crush seeds. Add the seeds, milk, butter, shortening, eggs, salt, remaining sugar and 5 cups of flour to yeast mixture. Beat until smooth. Stir in enough remaining 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 dough in half. Shape each portion into 18 balls. Roll each into an 8-in. rope; coat with cinnamon. Tie in a knot and tuck ends under. Place 2 in. apart on greased baking sheets. Cover and let rise in a warm place until doubled, about 30 minutes.
Bake at 375° for 15-20 minutes or until golden brown. Remove from pans to wire racks. Meanwhile, in a small bowl, combine icing ingredients; drizzle over warm rolls. Yield: 3 dozen.