Preheat the oven to 350F. In a large skillet, cook the ground beef over medium heat for 8 to 10 minutes, or until browned; drain off any excess liquid. Stir in the salt, pepper, spaghetti sauce, and tomatoes until well blended; set aside. In a medium sized bowl, combine the spinach, ricotta and Parmesan cheeses and the egg; mix well. Spread 2 cups of the sauce mixture over the bottom of a 9" x 13" baking dish that has been coated with nonstick cooking spray. Place 4 of the uncooked noodles lengthwise over the sauce and 1 noodle crosswise across the end of the baking dish, completely covering the sauce and pressing the noodles into it. Spread the spinach mixture evenly over the noodles, then sprinkle with 1 cup of the mozzarella cheese. Cover evenly with 1 1/2 cups of the sauce mixture, then arrange the remaining noodles over the sauce, pressing lightly into the sauce. Spread the remaining sauce over the top. Bake for 45 minutes or until the noodles are tender. Remove from the oven and sprinkle with the remai ning 1/2 cup mozzarella; cover with aluminum foil and let sit at room temperature for 15 minutes before cutting and serving.