This dish derives its name from the marmita, a type of pot used for stews. Its roots trace back to men who prepared it aboard tuna fishing boats. There are many versions of marmitako, and ingredients vary according to what is available. But most renditions include tuna, potatoes, garlic, and peppers. Although crushed red pepper flakes are not traditional, they add a little kick.
Heat oil in a large Dutch oven over medium heat. Add carrot; cook 5 minutes, stirring occasionally. Add onion, bell pepper, and chile; cook 15 minutes or until vegetables are tender, stirring occasionally. Add potato, garlic, and bay leaf; cook 3 minutes, stirring frequently. Add broth, wine, salt, and red pepper flakes, stirring to combine; bring to a boil. Cover, reduce heat, and simmer 10 minutes or until potatoes are tender, stirring occasionally. Remove from heat. Discard bay leaf. Stir in parsley. Place 1/2 cup tuna into each of 4 bowls. Ladle 1 1/4 cups potato mixture into each bowl.