Cook pasta in a large saucepan of salted boiling water following packet instructions until almost cooked through, or quite al dente. Drain and set aside.
Meanwhile, heat oil in a medium saucepan.
over medium heat. Add garlic and cook, stirring for 2 minutes. Increase heat.
to high and add beef. Cook, stirring to break up any lumps, for 3-5 minutes.
or until brown.
Add oregano, thyme and rosemary. Season to taste with salt and pepper. Add tomatoes and stock and bring to the boil.
Reduce heat to low and simmer for 5 minutes.
Spoon a small amount of tomato mixture into bottom of a 3 litre capacity casserole dish (just enough to cover the surface). Top with half of penne. Layer with half of remaining tomato sauce and half of mozzarella cheese. Layer remaining penne on top. Spoon over remaining sauce and mozzarella cheese. Bake in oven until cheese is golden and bubbly, about 30 minutes. Serve with a simple mixed salad tossed with fat-free dressing.