In skillet, heat 1/4 cup olive oil over low heat; cook onion, stirring occasionally, for about 30 minutes or until golden. Let cool. Meanwhile, in large bowl, disolve sugar in warm water. Sprinkle with yeast and let stand for 10 minutes or until frothy. Stir in 2 tbsp olive oil and salt. Add 2 cups of the flour and beat with electric mixer for 2 minutes or until smooth and elastic. Gradually stir in remaining flour, onions and rosemary.
Turn out onto lightly floured surface and knead lightly until smooth and elastic, adding flour as needed for 8 to 10 minutes.
Place in greased bowl, turning to grease all over. Cover and let rise for 35 to 45 minutes. Punch down. Divide in half; pat each half into flat round. Let rest for 5 minutes; stretch into 10-inch rounds. Place on greased baking sheets sprinkled with cornmeal. Cover and let rise for 35 to 45 minutes. Brush tops with olive oil; sprinkle with coarse salt and rosemary. Bake in 375 F (190 C) oven for 25 to 30 minutes or until bottom is browned and crisp. Let stand for 10 minutes. Cut into wedges to serve.
Makes 2 rounds.