Preheat the oven to 350°F. Lightly spray a 9×13-inch baking dish with baking spray or coat with a touch of olive oil, and then set the dish aside.
Bring a large pot of salted water to a boil. Once boiling, add the manicotti and cook until al dente, according to the package instructions. Then drain manicotti and dry on a single layer of paper towels. Add the fresh baby spinach into the same boiling water to blanch, about 1 minute. Meanwhile, fill a small bowl with ice water. Then use a slotted utensil or spider strainer to transfer the blanched spinach into the ice water bath to stop the spinach from cooking any further. Drain the ice water and wrap wilted spinach in a bunch of paper towels to gently squeeze out excess moisture.
In a large mixing bowl, combine the spinach, ricotta cheese, shredded mozzarella cheese (saving about ⅓ cup for the topping!), parmesan, parsley, basil, garlic paste, oregano, red pepper flakes (if using), and salt/pepper- to taste. Stir the filling together until well combined.
Add the filling into a large piping bag (or use a large plastic baggie). Grab the prepared baking dish and pour in about ½ of the tomato sauce, coating the bottom surface of the pan edge to edge. Then fill the manicotti shell with the spinach filling, gently pressing the filling into the hole being careful not to break the pasta shell (but it’s okay if that happens, too!). Then place filled manicotti shells right on top of the tomato sauce in the baking pan. Repeat the process until all shells are filled and assembled in the dish. Pour remaining tomato sauce over shells and sprinkle reserved shredded mozzarella over shells.
Place the baking dish into the oven, uncovered, to bake for 20-25 minutes or until the sauce is somewhat bubbly and the manicotti is lightly golden and delicious-looking!
This three-cheese and spinach manicotti immediately. It’s incredible as-is, but also when paired alongside a side salad and garlic bread for a complete meal, mmm. Enjoy!
