Prepare the manicotti noodles according to package directions until al dente. Drain and allow them to cool slightly so they are easier to handle.
In a mixing bowl, combine the cottage cheese, ricotta cheese and spinach. Mix until evenly combined.If using frozen spinach, make sure it is thawed and well-drained to prevent excess moisture.
Carefully spoon or pipe the cheese and spinach mixture into each cooked manicotti shell.
In a bowl, combine the crushed tomatoes, Herbes de Provence, basil and diced garlic. Mix well to create a simple, flavorful tomato sauce.
Spread a small amount of sauce on the bottom of a 12-inch Dutch oven or 9x13-inch baking dish. Arrange the filled manicotti in a single layer. Pour the remaining sauce over the pasta and sprinkle the grated mozzarella cheese evenly on top.
Bake at 350°F for 35–40 minutes, until the cheese is melted and bubbly and the sauce is heated through. Let the manicotti rest for 5–10 minutes before serving.