Heat oil in heavy medium saucepan over medium heat. Add onion and sauté until tender, adding 1-2 Tbsp water if onion sticks, about 3 minutes.
Add garlic, basil, and oregano and sauté 1 minute.
Add beef and cook until brown crumbling with fork, about 4 minutes. Add wine and bring to boil.
Add tomatoes and their juices and tomato paste and extra can of tomato sauce (if needed). Simmer until sauce is reduced, about 30-40 minutes. Season with salt and pepper. Total sauce to be used in casserole measures 3 cups. You may have more which can be used for other things. Can be prepared 2 days ahead. Cover and refrigerate.
Cook zucchini in large pot of boiling salted water until just tender about 2 minutes. Drain. Rinse under cold water. Transfer zucchini to paper towels and drain well.
Spread 1 cup of sauce in 9×13” glass baking dish. Top with 15 zucchini slices, overlapping slightly. Season with salt & pepper. Repeat laying, using 1-cup sauce, remaining 15 zucchini slices and 2 Tbsp cheese. Spread remaining 1 cup sauce.
Sprinkle with remaining 4 Tbsp cheese. Bake zucchini until top bubbles and is golden brown about 30 minutes.