In large bowl, dissolve yeast and sugar in water; let stand for 5 minutes. Add oil and salt. Stir in flour, a cup at a time, to form soft dough. Turn onto floured board; knead until smooth and elastic, about 2-3 minutes. Place in greased bowl, tuning once to grease top. Cover and let rise in a warm place until doubled, about 45 minutes.
Meanwhile, brown beef and onion; drain. Punch dough down; divide in half. Press each into a greased 30 cm pizza pan. Combine the tomato sauce, oregano and basil; spread over each crust. Top with beef mixture, green pepper and cheese.
Bake at 200ºC or 25-30 minutes or until crust is lightly browned.
Yield 2 pizzas.