Place squash cut-side down in a microwave-safe dish; add 2 tablespoons water. Microwave, uncovered, on High until tender, 10 to 15 minutes. (Alternatively, place squash halves cut-side down on a rimmed baking sheet. Bake at 400°F until tender, 40 to 50 minutes.)

Meanwhile, preheat oven to 400°F.

Make the filling mixture by stirring the artichoke hearts, cream cheese, ¼ cup Parmesan, salt, pepper, garlic granules, and onion granules together in a large bowl.

Combine spinach and the remaining 1 tablespoon water in a large skillet over medium heat. Cook, stirring occasionally, until wilted, 3 to 5 minutes. Drain and transfer to the mixture.

Use a fork to scrape the squash from the shells into the mixture. Place the shells on a baking sheet. Divide the mixture between the squash shells and top with the remaining ¼ cup Parmesan. Bake at 400°F for 15 minutes.

Finally, broil until the cheese is golden brown, about 3 minutes. Sprinkle with crushed red pepper and basil.