Begin by bringing a large pot of salted water to a boil. Carefully add the cannelloni or manicotti shells. Cook them according to the package instructions, usually around 8-10 minutes, until they are al dente. If using lasagna sheets, cook them just enough to soften, as they'll be filled and baked later. Once cooked, drain the pasta and set it aside to cool slightly.
In a skillet over medium heat, add the lean ground turkey or chicken. Use a wooden spoon to break it apart as it cooks. Season the meat with garlic powder, black pepper, dried sage, crushed red pepper flakes, fennel seeds, dried oregano, and salt. Cook for about 7-10 minutes, or until the meat is fully cooked and no longer pink. Stir frequently to ensure even cooking.
Preheat your oven to 375°F (190°C). In a baking dish, spread a thin layer of the tomato-basil sauce on the bottom. Using a spoon or piping bag, carefully fill each cannelloni shell with the turkey mixture. Arrange the filled cannelloni in the baking dish in a single layer. Pour the remaining tomato-basil sauce over the top, ensuring all shells are well-covered.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes. After 25 minutes, remove the foil and bake for an additional 10-15 minutes, or until the sauce is bubbly and the cannelloni is heated through. If you like a bit of char on top, feel free to broil for a couple of minutes at the end.
Once out of the oven, let the dish cool for a few minutes. Garnish with torn basil leaves for a fresh touch. Serve warm, and enjoy the comforting flavors of this Cannelloni with Basil Tomato Sauce!