Preheat oven to 400°F and line a large, rimmed baking sheet with parchment paper or a Silpat® baking mat. Set aside
Heat 2 tablespoons olive oil in a large skillet over medium heat. Add the onion and celery, and season with salt and black pepper, to taste. Cook, stirring occasionally, until the onion is soft and translucent, approximately 4-5 minutes
Add another tablespoon of olive oil to the skillet, along with the garlic and eggplant. Cook, stirring occasionally, until the eggplant begins to cook down, around 6-7 minutes.
Add the tomatoes, tomato paste, passata, vinegar, capers, green olives, and raisins. Stir to combine and cover skillet with a lid. Reduce heat to low and simmer gently for 15 minutes.
Meanwhile, lightly brush each cod fillet with the remaining olive oil and season with salt and black pepper on both sides. Place the fillets on the prepared baking sheet and place in the pre-heated oven to roast until the fish turns opaque and flakes easily with a fork, approximately 12-13 minutes. (Test after 10 minutes. Do not overcook)
Remove lid and stir in two tablespoons each of the fresh parsley and the toasted almonds into the caponata. Taste and adjust seasonings, as desired.
Transfer to individual serving plates and garnish with remaining parsley and almonds. Serve immediately with the cod fillets. Enjoy!