Ingredients
1 (28-oz can) whole peeled tomatoes
1 tablespoon extra-virgin olive oil
1 pound sweet or spicy Italian sausage (or a combination), removed from casings
1 tablespoon minced garlic
1 (15-oz. can) tomato sauce
Kosher salt and freshly ground pepper
1 pound ziti or rigatoni
2 tablespoons unsalted butter
2 tablespoons unbleached all-purpose flour
2 1/2 cups whole milk
1/8 teaspoon freshly grated nutmeg
1/3 cup plus 1 1/2 cups grated Parmigiano-Reggiano (about 5 ounces), divided, plus more for sprinkling
1 cup packed fresh basil leaves, chopped, plus more whole leaves for serving
1 pound fresh mozzarella, cut into 1/2-inch pieces and divided
Preparation
Transfer whole peeled tomatoes (with their juices) to a large bowl and squeeze with your hands to break up; set aside. Heat oil in a pot over medium-high. Add sausage and cook, breaking up with the back of a spoon, until browned in places and cooked through, about 8 minutes. Add garlic and cook, stirring, until fragrant, about 1 minute.
Add reserved crushed tomatoes to pot along with can of tomato sauce and 1/2 cup water (pour water into sauce can and swirl to catch any left inside). Season generously with salt and pepper; let simmer until flavors meld, skimming fat as needed, about 20 minutes.
Meanwhile, preheat oven to 425°F. Cook pasta in a pot of salted boiling water about 5 minutes less than package instructions (so it still has some bite in the center and won’t overcook in the oven). Reserve 1 cup pasta water, then drain and rinse noodles under cool water to stop cooking.
In now-empty pot, melt butter over medium heat. Add flour and whisk until combined and lightly toasted, 2 to 3 minutes. Slowly whisk in milk. Bring to a boil, then reduce heat and simmer, stirring often, until consistency is like slightly thickened cream, 10 to 15 minutes. Remove from heat. Season with salt, nutmeg, and 1/3 cup Parmigiano. Press plastic wrap directly on surface to prevent a skin from forming.
In a large bowl, toss pasta with 3 cups tomato sauce, 1/2 cup Parmigiano, 1/2 cup reserved pasta water (or up to 1 cup, if sauce is very thick), and basil. Season with salt and pepper.
Spread half of bechamel in the bottom of a 3-to-3 1/2-quart baking dish. Top with half of pasta mixture, 1 cup tomato sauce, half of mozzarella, and 1/2 cup Parmigiano. Layer with remaining pasta and 1 cup tomato sauce.
Spoon the last of the bechamel evenly on top, followed by remaining mozzarella and 1/2 cup Parmigiano; top with a few spoons of tomato sauce. Sprinkle with more Parmigiano. Place dish on a rimmed baking sheet lined with parchment (to catch spills).
Bake, uncovered, until browned in places and bubbly, about 30 minutes. Let cool 20 minutes, top with more basil leaves, and serve.