Preheat oven to 350F/180C. Spray an 8" x 8" baking dish with olive oil or non-stick spray. Wash the squash and cut in slices or half-moon slices. Wash basil, spin dry or dry with paper towels and finely chop. Slice green onions.
Combine the sliced squash, chopped basil, sliced green onions, dried thyme, garlic powder, and both kinds of cheese and stir together until the veggies are coated with cheese and the herbs are well-distributed. Season with salt and fresh ground black pepper. Put the mixture in the baking dish and bake uncovered for about 25-30 minutes.
When the zucchini is nearly cooked through, take the casserole dish out of the oven and sprinkle over the remaining 1/2 cup of grated cheese. Put the dish back in the oven and bake 10-15 minutes longer, or until the cheese is melted and nicely browned and zucchini is fully cooked. Serve hot.