Instructions

• Preheat the oven to 375°F (190°C) and place a rack in the middle position.
• Make the sauce: Heat about 1 1/2 tablespoons olive oil in a medium saucepan over medium heat. Add 1 small chopped onion and sauté until soft and fragrant. Add 5 minced garlic cloves, 1/4 teaspoon red pepper flakes, and 1 teaspoon Italian spices mix; stir in 1 tablespoon tomato paste and sauté 1 minute. Add the 28-ounce can crushed tomatoes, bring to a simmer, reduce heat to low, and simmer uncovered about 20 minutes. Season with salt and pepper to taste and keep warm.
• Reserve 1 cup of the shredded cheese (from the 4 cups pre-packaged Italian blend, or the alternative 2 1/2 cups mozzarella + 1 1/2 cups provolone) and set it aside for topping.
• Make the filling: In a large bowl combine 3 cups ricotta cheese, the remaining 3 cups shredded cheese, 1 large egg (lightly beaten), 1/2 teaspoon salt, and 1/2 teaspoon pepper. Fold in 3 loosely filled cups baby spinach, finely chopped, until evenly blended.
• Prepare the noodles: Place the 16 no‑boil oven‑ready lasagna noodles in hot water for about 5 minutes to make them pliable for rolling. Drain and lay the noodles flat on a clean kitchen towel or parchment to remove excess surface water.
• Assemble the manicotti: Spread half of the sauce evenly on the bottom of a 9" x 13" baking dish. Working with one noodle at a time, place about 1/4 cup of the cheese and spinach filling along the short (narrow) edge of the noodle, leaving a small margin at the edges, then roll the noodle up tightly from the short side. Place each rolled noodle seam-side down in the baking dish over the sauce. Repeat until all 16 noodles are filled and arranged in a single layer.
• Finish and bake: Spoon the remaining sauce over the rolled noodles, cover the baking dish tightly with foil, and bake at 375°F for about 40 minutes. Remove the foil, sprinkle the reserved 1 cup of shredded cheese evenly over the top, and bake an additional 5 minutes (or until the cheese is melted).
• Rest and serve: Remove from the oven and let the casserole rest about 10 minutes before serving.