1. Cook pasta according to package directions; drain.
2. Meanwhile, cook sausage in skillet until browned; drain off fat. Stir in tomato paste, undrained tomatoes, beans, rosemary and cooked pasta; heat through.
3. Spread half the mixture in 2-quart casserole. Combine ricotta, 1/2 cup mozzarella and egg; spoon over sausage mixture. Spread remaining sausage mixture on top.
4. Bake, covered, at 350F, 30 minutes. Combine bread crumbs and butter. Uncover and sprinkle with remaining mozzarella; top with bread crumbs. Bake 5 minutes more to melt cheese. Let stand 5 minutes.