Preheat oven to 475 degrees.
In a shallow bowl, lightly beat eggs with 1 teaspoon salt and ¼ teaspoon pepper.
Spread breadcrumbs in a pie plate or shallow bowl.
Oil a rimmed baking sheet.
Dip eggplant rounds in egg, then dredge in breadcrumbs, turning to coat completely; transfer to prepared baking sheet.
Bake (without turning) until golden and tender, 15 to 20 minutes.
Meanwhile, split bread lengthwise, and place cut side up on another baking sheet; press gently in centers to create a well.
Layer both halves with tomato sauce, eggplant, and cheese.
Bake until cheese is browned in spots, 6 to 8 minutes.
