Preheat your oven to 375°F.
For the eggplant preparation, whisk together the beaten eggs and water in a shallow bowl. In another dish, mix the whole-wheat panko with ¼ cup of grated Parmigiano-Reggiano. Dip each eggplant slice into the egg mixture, then coat it in the breadcrumb mixture, pressing gently to ensure the crumbs stick well. Place the coated eggplant slices on a baking sheet lined with cooking spray, spacing them about 1 inch apart. Bake for 30 minutes, flipping once halfway through, until the eggplant slices turn golden and crispy.
While the eggplant is baking, prepare the filling by combining the torn basil, ricotta cheese, minced garlic, crushed red pepper, grated Parmigiano-Reggiano, salt, and a beaten egg. Stir the mixture until well blended.
To assemble the dish, coat a 13 x 9-inch glass baking dish with cooking spray. Spread ½ cup of pasta sauce evenly across the bottom of the dish. Arrange half of the baked eggplant slices over the sauce, then sprinkle ⅛ teaspoon salt over the eggplant. Pour about ¾ cup of pasta sauce on top, followed by half of the ricotta filling. Layer a third of the mozzarella slices and ¼ cup of fontina cheese over the ricotta. Repeat the process with the remaining eggplant, sauce, and ricotta mixture. Finish with a final layer of pasta sauce on top.
Cover the baking dish tightly with aluminum foil coated with cooking spray, and bake for 35 minutes at 375°F. Afterward, remove the foil and top the dish with the remaining mozzarella and fontina. Continue baking for another 10 minutes, or until the cheese is melted and bubbly. Allow the dish to cool for 10 minutes before serving.