Tuna In Tomato Sauce Recipe Ingredients: 1 onion 3 clv garlic 1 green bell pepper 1 red bell pepper 1 1/2 lb tuna fillet (boneless) 4 T olive oil 1/2 t salt 1/4 t ground black pepper 1/4 t salt 1 lb tomato sauce Instructions: Peel and chop 1 onion.Peel and chop 3 cloves of garlic.Deseed, wash and chop green and red peppers.Dice tuna fillets into 1-inch cubes approximately.Heat 4 tablespoons of olive oil in a large skillet. When warm, add chopped garlic, onion and 1/2 teaspoon of salt. Cook and stir over low heat for 4 - 5 minutes.Add chopped peppers and cook and stir over low-medium heat for 8 - 10 minutes more.Add tuna dices, season with 1/4 teaspoon of salt and 1/4 teaspoon of ground black pepper and cook and stir over medium heat for 4 - 5 minutes.Add tomato sauce and cook over low-medium heat for 8 - 10 minutes or until tender.Serve warm and enjoy your tuna stew with tomato sauce. See more Spanish fish stew recipes! Description: Tuna fish stew in tomato sauce, a typical fish stew recipe from Spain in a yummy and easy tomato sauce with onions and peppers. Notes: If you like tuna stew, take a look to our homemade Marmitako recipe, the famous Basque tuna stew with potatoes!