Bring 4-5 cups water to a boil in a large pot. Add manicotti shells and continue to boil 10-12 minutes or until shells are tender and bendable but not quite completely cooked (you want them to be able to hold their shape somewhat when you fill them).
Preheat oven to 350 and lightly spray a 9x13 inch casserole dish or baking dish with cooking spray.
In a large bowl combine cottage cheese, spinach, 2 cups mozzarella, parmesan cheese, basil, oregano, pepper, salt, and garlic powder. Use a hand mixer to mix all ingredients 2-3 minutes or until all ingredients are incorporated.
Pour 2/3 of sauce into the prepared baking dish. Use a spoon to carefully fill each manicotti shell with about 2-3 tablespoons of filling. Lay stuffed shells side by side in the baking dish. Add 1/3 cup water to dish. Cover shells with remaining sauce and top with remaining mozzarella cheese.
Bake uncovered about 30 minutes or until shells are completely cooked, cheese is melted, and filling is hot. Serve hot and top with fresh basil if desired.