Preheat oven to 425°. Slice spaghetti squash lengthwise, then scoop out and discard seeds. Drizzle cut sides with oil and season with salt and pepper.
Place squash cut-side down on a large, rimmed baking sheet. Roast until tender, 43 to 45 minutes. Let cool slightly. Using a fork, break up squash strands.
Meanwhile, in a large skillet over medium heat, heat RAGÚ Classic Alfredo Sauce until bubbly. Add squash and Parmesan and toss to coat. Add spinach and stir until wilted, about 5 minutes.
Transfer mixture back into squash halves and sprinkle with mozzarella. Bake until cheese is golden and bubbly, 10 to 12 minutes more. If a more golden top is desired, broil top 2 to 3 minutes more. Garnish with fresh basil.
Recipe by 5* trending recipes with videos at https://food.theffeed.com/2017/05/04/cheesy-baked-spaghetti-squash/