For the roasted eggplant:
Preheat the oven to 425 degrees. Toss the eggplant with a few tablespoons of oil and season with salt and pepper. Spread the eggplant onto sheet pan in an even layer and roast, stirring occasionally, until golden brown and soft, about 25 minutes.
Bring 4 quarts of water to a boil in a large pot and add 2 tablespoons of kosher salt. (If using fine salt, use 1 tablespoon). Stir in the pasta, cover the pot and bring to a boil. Cook until just slightly under al dente (it will continue cooking in the sauce) for about 8 minutes. Remove 1 cup of the pasta water and reserve. Drain the pasta well.
For tomato sauce:
1. Heat the oil over medium-high heat in a large high sided sauté pan. Add the onion and cook until soft, about 5 minutes. Add the garlic and cook for 30 seconds.
2. Add the tomatoes and half of the reserved juice and bring to a simmer, cook for 1 hour and then gently crush the tomatoes with a potato masher until slightly smooth. Taste for seasoning and add sugar if needed. Add the chile flakes and continue cooking until the mixture thickens, about 25 to 30 minutes longer, stirring occasionally. Season the sauce with the salt and pepper to taste.
3. Add the drained pasta to the sauce and toss to coat evenly. Stir in some of the reserved pasta water, if needed, and ½ cup of the cheese. Stir in the arugula, eggplant and herbs. Transfer to a platter and top with dollops of ricotta and serve with the remaining cheese on the side.