Baked Ziti with Eggplant and Ricotta - Lidia

Ingredients

• Kosher salt
• 3 tablespoons extra-virgin olive oil, plus more for brushing the baking dish
• 2 small Italian eggplant (about 1 pound total)
• Vegetable oil, as needed
• 1 medium onion, chopped
• 1 (28-ounce) can whole San Marzano tomatoes, crushed by hand
• ¼ teaspoon crushed red pepper flakes
• 1 pound ziti
• ¼ cup fresh basil leaves, shredded
• 1 cup fresh ricotta
• 1 cup grated provolone
• ¼ cup grated Grana Padano