01 -
Set oven temperature to 175°C (350°F).
02 -
In a bowl, thoroughly combine spaghetti sauce with water until well integrated. Set aside.
03 -
In a large bowl, combine chopped spinach, ricotta cheese, one-third of the shredded mozzarella, Parmesan cheese, egg, pesto, oregano, garlic powder, and season with kosher salt and freshly cracked pepper.
04 -
Transfer the filling mixture to a piping bag or a gallon-sized ziplock bag.
05 -
Spread half the diluted spaghetti sauce in an even layer across the bottom of a 23×33 cm (9×13 inch) baking dish.
06 -
Cut the tip off the piping bag to match the width of the manicotti noodles. Pipe the filling into each uncooked manicotti tube.
07 -
Place the filled manicotti tubes in the baking dish, then pour the remaining sauce evenly over the noodles.
08 -
Distribute the remaining shredded mozzarella over the manicotti. Cover the baking dish tightly with aluminum foil.
09 -
Bake for approximately 50 minutes or until the noodles are nearly cooked through.
10 -
Remove the foil and continue baking for an additional 5-10 minutes until the noodles reach al dente texture. For a golden top, broil on high for 1 minute if desired.
11 -
Allow the dish to rest for a few minutes before garnishing with fresh chopped parsley and grated Parmesan cheese.