Heat 2 tablespoons of olive oil in a medium saucepan over medium heat. Add the onion and garlic, and cook, stirring frequently, until golden. Add the tomatoes and reduce heat to low. Simmer for about 20 minutes, until the tomatoes begin to break down, and some liquid has reduced. Season with salt and pepper and set aside.
Preheat grill to medium-high heat.
Sprinkle the eggplant with salt and pepper, and drizzle with 3 tablespoons of the olive oil. Grill for 10-15 minutes, until the skin is charred and the eggplant is tender.
To serve, spoon tomato sauce on top of the eggplant halves, then top with ricotta and fresh basil. Enjoy!