1 small red onion, thinly sliced and separated into rings
3 to 4 medium plum tomatoes, thinly sliced
In a large bowl, combine 2-1/2 cups flour, salt and sugar. Dissolve yeast in water; stir in oil. Add to dry ingredients; 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; let rise in a warm place until doubled, about 30 minutes.
Punch the dough down. On a lightly floured surface, roll dough into a 12-in. circle. Place on a greased 12-in. pizza pan. Brush with oil. Combine the Parmesan cheese, rosemary, garlic and salt; sprinkle over dough. Arrange onion rings and tomatoes over top, pressing down lightly.
Bake at 400° for 15-20 minutes or until crust is golden brown. Cut into wedges.