Preheat oven to 350 degF.
Cook pasta according to package directions; drain and set aside.
Meanwhile, heat oil in a medium saucepan over medium heat; add garlic and cook 2 minutes. Add beef and cook until browned, breaking up meat with a spoon as it cooks, 3 to 5 minutes; drain off any fat and set pan back over medium heat.
Add oregano, they, rosemary, salt and pepper; stir to coat beef. Cook until herbs become fragrant, about 2 minutes. Add tomatoes and bring mixture to a boil; reduce heat and simmer for 5 minutes.
Soon a small amount of beef-tomato mixture into bottom of a 4-quart casserole dish (just enough to cover surface); top with half of cooked ziti. Next, layer with half of remaining beef-tomato sauce and half of mozzarella cheese. Layer with remaining ziti and then top with remaining beef-tomato sauce; sprinkle with remaining mozzarella cheese. Bake until cheese is golden and bubbly, about 30 minutes. Slice into 8 pieces and serve.