Preheat oven to 350 degrees. In a mixing bowl, combine ricotta, Parmesan, egg, spinach, salt and pepper.
Fold ingredients together until completely combined.
Coat the bottom of a casserole dish with 1/3 cup of the seasoned tomato sauce.
Lay lasagna noodle on a dry surface. Spread about 1 1/2 tbsp of the filling in a thin layer on the noodle. Starting from one end, delicately roll the noodle, and place on sauce in casserole dish.
All of the rolls will look like this :-)
Spoon the rest of the sauce over the roll ups, and sprinkle with mozzarella cheese. Cover with foil, and bake for 40 minutes, or until cheese is completely melted.
Voila! Serve with a simple salad or garlic toast. Super easy and a kid-approved staple!