Prepare the eggplants.
Preheat the oven to 400˚F and lightly grease a 9x13 baking dish with cooking spray; set aside.
Cut eggplants lengthwise into 1/4-inch thick slices; you should get about 16 slices total.
Arrange the slices on a baking sheet; sprinkle with salt on both sides and let stand for about 10 minutes. Then, using a paper towel, pat dry the eggplants.
Brush both sides of the eggplant slices with olive oil and transfer them back to the baking sheets in a single layer.
Roast the eggplant for about 8 minutes; flip over and continue to roast for 5 more minutes or until tender. Remove from oven and let cool.
Prepare the cheese filling.
Meanwhile, in a large mixing bowl, combine ricotta, feta, 1/2 cup mozzarella, 1/3 cup parmesan, garlic, eggs, salt, and pepper; mix and stir until well incorporated.
Spread 1/2 cup of marinara sauce onto the bottom of the baking dish.
Evenly divide the ricotta mixture among the eggplant slices and spread it down the center of each slice. Roll up the eggplant slices and place them seam-side down in the baking dish over the marinara sauce.
Use any leftover cheese mixture to spoon around the eggplant rollups.
Top the eggplants with the remaining marinara sauce and sprinkle with the remaining mozzarella and Parmesan.
Cover with aluminum foil and bake for 30 minutes. Remove the foil and continue to bake for 15 minutes, or until lightly browned and bubbly.
Remove from oven and let stand for about 10 minutes before serving.