Gather the ingredients. The Spruce / Julia Hartbeck In a saute pan over medium-low heat, heat oil; add bell peppers, onions, and whole garlic cloves and cook until the vegetables are limp. The Spruce / Julia Hartbeck Add crushed tomatoes, olives, and seasoning. Continue cooking until garlic cloves are easily pierced with a fork. Add a bit of water if the mixture becomes too dry. The Spruce / Julia Hartbeck Raise the heat to medium. Add the fish fillets to the pan. Saute until cod is cooked through and flakes easily with a fork. Season to taste with salt and pepper, if desired. The Spruce / Julia Hartbeck Serve cod filets with the Provencal sauce over the top. The Spruce / Julia Hartbeck