Combine the ricotta cheese, leeks, eggs, parsley, spinach, salt and pepper in a large bowl. Then stir in 3/4 cup of the mozzarella and parmesan cheese.
Mix the marinara sauce and water in a small bowl and spread a few spoonfuls over the bottom of a 9 x 13″ baking dish.
Fill the uncooked manicotti shells with the cheese mixture and place the shells in the baking dish. Pour the remaining marinara sauce over the noodles.
Cover the baking dish with foil and bake until the pasta is tender (about 50 minutes). Then sprinkle the manicotti with the remaining mozzarella and parmesan cheese and bake, uncovered, until the cheese is melted (about 10 – 15 minutes).
Notes
Recommended low FODMAP serving – 2 manicotti shells per sitting