recipe to die for Baked Rigatoni and Zucchini

1/2 teaspoon kosher salt, plus more for the pot
1/4 cup extra-virgin olive oil
1 medium onion, sliced
1 pound medium zucchini, sliced
1 (28-ounce) can whole San Marzano tomatoes, crushed by hand
1 cup loosely packed fresh basil leaves, roughly chopped  
1 pound dry rigatoni
1 tablespoon unsalted butter
8 ounces shredded fontina cheese
1 cup grated Grana Padano or Parmigiano-Reggiano cheese
Preheat the oven to 400 F. Bring a large pot of salted water to a boil for pasta.
In a large skillet, heat the olive oil over medium heat. Add the onion, and cook until it begins to soften, about 5 minutes. Add the zucchini, and cook until it begins to soften, another 5 minutes. Add the salt, then the crushed tomatoes, slosh the tomato can out with 1 cup water and add it to the skillet as well. Bring the sauce to a boil, and simmer just until it thickens, about 8 to 10 minutes, but don’t let the zucchini begin to fall apart. Then toss in the chopped basil.
Meanwhile, cook the rigatoni until al dente, a few minutes shy of the package directions. Drain the pasta and toss it in the skillet with the tomato sauce and basil.
Butter a 9x13-inch baking dish. In a medium bowl, toss together the two cheeses. Spread half the pasta and sauce in the baking dish, and top with half the cheese. Layer the remaining pasta and sauce, then the remaining cheese.
Bake, uncovered, until browned and bubbly, about 20 minutes.
Makes 6 to 8 servings.

PER SERVING: Calories 539 (40% from fat), Fat 24 g (11 g sat), Cholesterol 52 mg, Sodium 853 mg, Fiber 4 g, Carbohydrates 58 g, Protein 24 g