Step 1
Position racks in the middle and upper third of oven; preheat to 425 degrees F. Coat 2 rimmed baking sheets with cooking spray.

Step 2
Slice each eggplant lengthwise into 1/4-inch-thick strips. Discard any small or misshapen pieces. You should have about 24 strips. Sprinkle the strips with 1/4 teaspoon salt and let stand for 15 minutes.

Step 3
Pat the eggplant slices dry and brush both sides with oil. Place on the prepared pans, overlapping the slices a little if necessary. Roast until soft and beginning to brown, swapping the pans from top to bottom midway, about 20 minutes. Let cool slightly.

Step 4
Meanwhile, combine tomatoes, 1/4 cup basil, 2 teaspoons garlic and the remaining 1/4 teaspoon salt in a large bowl. Spread 1/2 cup of the mixture in a broiler-safe 9-by-13-inch baking pan. Squeeze spinach to remove any excess liquid. Combine the spinach, ricotta, Parmesan, pepper and the remaining 1 teaspoon garlic in a medium bowl.

Step 5
When the eggplant is cool enough to handle, spread a generous tablespoon of the ricotta mixture on each slice. Starting from the narrowest end, roll up the slices and place in the baking pan seam-side down. Top with the remaining tomato mixture.

Step 6
Bake the rolls on the middle rack until the tomato mixture is hot and bubbling, 40 to 45 minutes. Remove from the oven and preheat the broiler to high.

Step 7
Top the rolls with mozzarella. Broil until the cheese is bubbling and beginning to brown, 1 to 2 minutes. Sprinkle with the remaining 1/4 cup basil and serve.