Step 1

Slice ends off eggplants. Cut eggplants lengthwise into 1/4-inch-thick slices, discarding peel-covered ends. You should get roughly 16 slices total. Lay slices on a rimmed baking sheet and sprinkle both sides liberally with salt. Let stand for 15 minutes, then rinse salt off under cold running water and pat slices dry.

Step 2

Preheat oven to 400ºF. Brush both sides of eggplant slices with olive oil and place in single layers on 2 baking sheets. Roast for 15 minutes, until tender, turning eggplant slices over halfway through. Let cool on sheets on wire racks until cool enough to handle.

Step 3

In a large bowl, combine spinach, ricotta, garlic, eggs, 1/2 cup mozzarella and 1/2 cup Parmesan. Season with 1 tsp. salt and 1/2 tsp. pepper. Mist a 9-by-13-inch baking dish with cooking spray. Spread 1/2 cup of sauce over bottom of dish. Divide ricotta mixture among eggplant slices, using about 1/3 cup for each, spreading it down the center. Roll up slices and place seam-side down in baking dish. Top with remaining sauce and sprinkle with remaining mozzarella and Parmesan.

Step 4

Cover baking dish with foil and bake for 30 minutes. Remove foil and bake until browned and bubbling, about 15 minutes longer. Let cool for 10 minutes before serving.