Preheat your oven to 350°F (175°C). In a large pot, bring salted water to a boil and gently add the manicotti shells. Cook for 5 minutes, allowing them to become al dente. Once done, carefully drain the shells, and let them cool for about 10 minutes.

In a mixing bowl, combine 15 ounces of whole milk ricotta cheese, 1 large egg, 1 cup of shredded mozzarella, ½ cup of grated parmesan, chopped fresh basil, Italian seasoning, kosher salt, and black pepper. Stir until everything is fully incorporated and creamy.

Grease a 9x13-inch casserole dish with cooking spray or a light coating of olive oil. Spread 1 cup of marinara sauce evenly across the bottom of the dish.

Carefully take your cooled manicotti shells and pipe the cheese filling into each one, filling them generously. Arrange the filled shells snugly in the casserole dish over the marinara sauce. Pour the remaining marinara sauce over the top.

Sprinkle the remaining 1 cup of shredded mozzarella and ½ cup of grated parmesan cheese evenly over the top. Place the casserole dish in the preheated oven and bake for 40 minutes, until the cheese is melted and bubbly.

Switch your oven to broil and cook the manicotti for an additional 1 to 3 minutes to achieve a golden top, watching closely to prevent burning.

Before serving, sprinkle some fresh basil over the top. Plate it up with a side of garlic bread or a refreshing salad.