Preheat oven to 400 degrees F.
In a large skillet, add 1 Tbsp olive oil to the bottom and swirl around until covered.
Add the cod to the pan, and then add the tomatoes.
Pour the remaining 3 Tbsp olive oil over the cod and the tomatoes.
Season with salt and pepper.
Cook in the oven for 15 minutes, then remove and let stand for 2 minutes.
Plate, top with the basil leaves, and season with more salt and pepper if desired.