Prep and Soften the Eggplant: Preheat your oven to 400°F (200°C). Line two large baking sheets with parchment paper. Cut the ends off the eggplants and slice them lengthwise into thin, uniform planks about 1/4-inch thick. (Optional: Sprinkle slices with salt, let sit for 15 minutes to draw out moisture, then wipe completely dry). Arrange slices on the sheets, brush both sides with olive oil, and season with salt and pepper. Bake for 10 to 12 minutes until pliable and tender. Remove and let cool.

Make the Spinach Ricotta Filling: Reduce the oven temperature to 375°F (190°C). Place the thawed spinach into a clean kitchen towel and squeeze firmly until completely dry. In a medium bowl, thoroughly mix the squeezed spinach, ricotta, Parmesan, 1/2 cup of the mozzarella, the egg, minced garlic, salt, black pepper, and a tiny pinch of nutmeg until uniform.

Assemble the Rollatini: Spread 1 cup of the marinara sauce evenly across the bottom of a 9x13-inch baking dish. Lay an eggplant slice flat on your work surface. Spoon about 2 tablespoons of the spinach filling onto the wider end of the slice, roll it up tightly, and place it seam-side down into the baking dish. Repeat for all remaining slices.

Sauce and Bake: Spoon the remaining 1 cup of marinara sauce evenly down the center line of the rolled eggplant rows. Top the sauced areas with the remaining 1/2 cup of shredded mozzarella and an extra dusting of Parmesan cheese. Bake uncovered for 20 to 25 minutes until the sauce is bubbling and the cheese is fully melted and golden brown.

Garnish and Serve: Remove from the oven and let rest for 5 minutes to allow the filling to set. Garnish generously with fresh whole basil leaves right before serving.