Cook the noodles according to the package instructions to al dente with 1 teaspoon of salt, drain and keep in a pot with room temp water. This will help the noodles not stick together.
Preheat the oven to 375°F/190°C.
In a dutch oven, heat the olive oil and cook the ground beef breaking it apart with a wooden spoon until it’s no longer pink. Drain fat if needed. Season with salt and pepper.
Add the onion, and cook for 2-3 minutes or until it’s translucent, add the garlic and cook for 30 seconds.
Add the marinara sauce to the meat, bring to a simmer and cook for 5 minutes. Remove from heat.
In a medium bowl, combine the ricotta with the egg, parmesan cheese, 1 ½ cups of mozzarella and Italian seasoning. Give it a stir until the mixture is well combined and smooth. Set aside.
To assemble: Spread ½ cup of the meat sauce at the bottom of the casserole dish.
Arrange the noodles in a single layer over a baking sheet.
Spread evenly about ¼ a cup of the ricotta mixture over each noodle, followed by 1 heaping tablespoon of the meat sauce.
Roll each noodle up, and arrange in the casserole dish.
Cover with the remaining meat sauce, and top with 1 cup of shredded mozzarella cheese (if needed for photography, you can add a little more).
Loosely tent with foil and make sure that the foil is not touching the cheese, and bake for 30 minutes.
Uncover, and place under the broiler until the cheese starts to brown. Remove from the oven, sprinkle with parsley and serve.