Directions

1. For dough, in a very large mixing bowl, stir the yeast into 1/2 cup of the warm water; add the 1 teaspoon sugar. Let the mixture stand for 5 minutes or until the mixture is foamy.
2. Stir the cake mix, 1 cup of the flour, the egg, oil, salt, and the remaining water into yeast mixture. Beat with an electric mixer on high speed for 3 minutes, scraping sides of bowl constantly. Using a wooden spoon, stir in the remaining flour to form a soft dough. (Dough will be sticky.)
3. Cover and let rise about 1 hour or until doubled.
4. Lightly grease two 13x9x2-inch baking pans. Set aside. Stir dough down. Cover and let rise again until doubled (about 30 minutes). Stir dough again. Divide in half. Turn 1 portion of the dough out onto a well-floured surface*. Turn to coat lightly with flour. Roll or pat the dough into a 12x8-inch rectangle. Brush with half of the melted butter.
5. For filling, in a small mixing bowl, combine the 1 cup sugar and the cinnamon. Sprinkle half of the filling over dough. Roll up, jelly-roll style, starting from one of the long sides. Pinch edge to seal.
6. Cut crosswise into 12 pieces. Arrange, cut sides down, in a prepared pan. Repeat with the remaining dough, remaining butter and remaining filling. Cover loosely; let the dough rise in a warm place until nearly doubled (about 30 to 45 minutes).
7. Uncover pans. Place a baking sheet under each of the pans. Bake in a 350 degrees F oven for 25 to 30 minutes or until lightly brown and rolls sound hollow when lightly tapped.
8. Invert onto serving plates. Drizzle Powdered Sugar Icing over warm rolls. Serve warm.