Combine breadcrumbs and Parmesan cheese. Whisk together eggs and 3 tablespoons water. Dip eggplant into egg mixture, and dredge in breadcrumb mixture. Place on baking sheets coated with cooking spray. Coat eggplant with cooking spray.
Broil 12 inches from heat (with electric oven door partially open) 5 minutes on each side.
Place eggplant evenly on roll halves, and place rolls on baking sheet. Top with spaghetti sauce, and sprinkle evenly with mozzarella cheese.
Broil 3 to 5 more minutes or until cheese is melted and bubbly.