sheet pan spaghetti squash alla norma

0 Heat the oven to 450°F with racks in upper and lower thirds. 
1 Dice the eggplant into 1/2-inch pieces. Transfer to a baking sheet and drizzle with 2 tablespoons of the oil. Season with 1 teaspoon of the salt and several grinds black pepper and toss to coat with your hands. Set aside. 
2 Slice the stem off the spaghetti squash (this will help it sit upright on the baking sheet), then cut the squash in half crosswise. (To make it easier to slice, poke several holes in the squash with a fork and microwave 3 to 4 minutes before slicing). Scoop out the pulp and seeds. 
3 Brush the cut sides with the remaining 1 tablespoon oil (you may not need all of it) and season with the remaining 1/2 teaspoon of the salt and several grinds black pepper. Place cut side down on a baking sheet. 
4 Place the eggplant on the upper oven rack and the squash on the lower rack. Roast, tossing the eggplant halfway through, until the eggplant is tender and the squash flakes easily with a fork but is still al dente (don't overcook it!), 25 to 30 minutes. Meanwhile, grate the cheeses and chop the basil. 
5 Reduce the oven temperature to 425°F. When the squash is cool enough to handle, scrape the strands onto the baking sheet. Add the roasted eggplant and marinara sauce and toss to coat. Add the basil, oregano, red pepper flakes, half the mozzarella, and half the Parmesan and stir to combine. Taste and season with salt and pepper, then spread into a single layer. 
6 Sprinkle with the remaining cheeses. Return to the upper oven rack and bake until the sauce is bubbly and the top is lightly browned, 20 to 25 minutes. Top with basil before serving.