Dissolve sugar and yeast in 3/4 cup water in a large bowl; let stand 5 minutes. Lightly spoon flour into dry measuring cups, and level with a knife. Stir 2 cups flour, oil, and salt into yeast mixture to form a soft dough. Turn dough out onto a lightly floured surface, and knead until smooth and elastic (about 5 minutes). Add enough of remaining flour, 1 tablespoon at a time, to prevent the dough from sticking. Place dough in large bowl coated with cooking spray, turning dough to coat top. Cover dough, and let rise in a warm place (85°), free from drafts, 40 minutes or until doubled in bulk.
Punch dough down. Cover and let rise 40 minutes or until doubled in bulk. Divide dough into 2 equal portions; roll each portion into a 9-inch circle on a lightly floured surface. Place dough circles on a large baking sheet coated with cooking spray. Top and bake according to directions.