Preheat your oven to 400°F (200°C).

In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1-2 minutes until fragrant but not browned.

Add the diced tomatoes to the skillet and cook for another 5 minutes, stirring occasionally until the tomatoes start to soften.

Stir in the marinara sauce and bring the mixture to a gentle simmer. Season with salt and pepper to taste.

In a baking dish, arrange the cod fillets in a single layer. Pour the tomato and marinara sauce mixture over the cod, ensuring the fillets are well coated.

Sprinkle the chopped basil over the top of the dish.

Bake in the preheated oven for 20-25 minutes, or until the cod is cooked through and flakes easily with a fork.

If desired, serve hot with grated Parmesan cheese on top.