Prepare the Ingredients: Start by chopping the onion finely and mincing the garlic. Set these aside for easy access. Also, pat the cod fillets dry with a paper towel and lightly season them with a sprinkle of salt and pepper.

Heat the Olive Oil: In a large skillet or pan, heat 2 tablespoons of olive oil over medium heat. Once hot, add the chopped onion and sauté for about 3-4 minutes or until it becomes soft and translucent.

Add the Garlic: Add the minced garlic to the pan with the onion, stirring frequently for another 1-2 minutes until the garlic releases its aroma. Be careful not to let it brown, as garlic can quickly turn bitter.

Add the Tomatoes: Pour the canned crushed tomatoes into the skillet with the onion and garlic mixture. Stir well to combine and let the sauce simmer on medium-low heat for about 10 minutes. This will allow the flavors to meld together.

Season with Salt, Pepper, and Basil: Add salt and pepper to taste and stir in the chopped basil leaves. Save some basil for garnish if desired. Let the sauce continue to simmer on low heat while preparing the cod.

Add the Cod Fillets: Carefully place the seasoned cod fillets in the skillet, making sure each piece is nestled into the tomato sauce. Spoon some of the sauce over the fillets to coat them. Cover the skillet with a lid and cook for 8-10 minutes, or until the cod is cooked through and flakes easily with a fork. Be careful not to overcook the fish as it can become tough.

Serve: Once the cod is done, remove the skillet from the heat. Garnish with more fresh basil if desired, and serve hot. This dish pairs wonderfully with steamed vegetables, crusty bread, or over a bed of rice or pasta.