Heat a drizzle of olive oil in a pan. Add minced garlic and sauté until fragrant. Add fresh spinach and cook them for a few minutes, stirring occasionally. Alternatively , boil the spinach. Let them cool slightly, and squeeze out any excess liquid before chopping finely.
In a bowl, combine the sautéed spinach, ricotta cheese, nutmeg salt and pepper, then mix until smooth.
Heat olive oil in a saucepan over medium heat. Add minced garlic and sauté until fragrant. Stir in tomato purée and salt. Dilute the sauce with about ½ cup of water to prevent it from drying out in the oven. Simmer for 5-10 minutes. Add fresh basil during the last few minutes of cooking.
Using a piping bag or small spoon, fill the uncooked cannelloni tubes with the ricotta mixture.
Spread a thin layer of tomato sauce over the bottom of a baking dish. Arrange the filled cannelloni in a single layer on top of the sauce. Pour the remaining tomato sauce evenly over the cannelloni.
Top with a mix of mozzarella, provolone, and/or Parmesan cheese.
Bake in a preheated oven at 350°F (175°C) for 25 minutes. Broil for a few minutes until the cheese is golden.
Let the cannelloni rest for 5 minutes before serving.
