Preheat oven to 450 degrees. Coat a 9 x 9-inch baking dish with nonstick spray. You can use glass or metal.
Cook pasta. Cook for only 6 minutes so it will not be overcooked. No need to add salt to water! Drain and rinse in cold water. Drain again.
In a large bowl, whisk together Alfredo sauce, drained spinach, cottage cheese, milk, butter, and garlic. Add pasta and mix really well. Blend in egg, basil, salt, and pepper. Be sure it’s all mixed together well.
Transfer pasta to the prepared baking dish.
Sprinkle the top evenly with mozzarella cheese.
Bake casserole 25 minutes until golden brown. Let casserole rest for 10minutes. Cut into 6 serving. This casserole freezes great!