In a large non-stick skillet, heat 2 tablespoons of olive oil. Add the eggplant and cook over moderately high heat, stirring often, until the eggplant is tender and browned, about 4 minutes. Transfer the eggplant to a bowl. Heat the remaining 1 tablespoon of olive oil in the skillet. Add the garlic, shallot, and celery and cook over moderate heat, stirring often, until the shallot is softened, 4 minutes. Stir in the tomato and cook for 30 seconds. Add the tomato mixture to the eggplant along with the olives, basil, lemon juice, and fennel seeds. Stir gently. Season the relish with salt and pepper and serve. Make Ahead: the relish can be refrigerated overnight.