Place your eggplant in a colander and salt them for 20 minutes. Once the time is up, rinse and pat the eggplants dry.
Heat 2 tbsp of oil in a large skillet over medium-high heat. Once the oil is heated, add half the eggplant to the skillet and cook until browned. Remove from the skillet and repeat this process with the other half of the eggplant.
Pour in the rest of the oil, then sauté the onion and celery for about 5 minutes or until they are soft.
Add the bell pepper and garlic and cook for 3 minutes.
Put eggplant back into the pan. Then add the vinegar, tomato paste, sugar, olives, and capers. Stir occasionally and simmer for 15 minutes.
Stir in basil and pine nuts. Season with salt and pepper.