SERVES 6
Like many Spanish fish stews—from suquet (see page 165) in Catalunya to caldereta (see page 28) in the Balearic Islands—the roots of this Basque dish lie with the humble fisherman. The name comes from the large cooking pots called marmitas used on boats from Basque puertos pesqueros (fishing ports) like Bermeo, Mundaka, and Lekeitio along the coast of Vizcaya. Potatoes kept well at sea, and fresh bonito was easy to catch in summer. This recipe calls for Spanish pimentón dulce (sweet paprika), but you often find the stew prepared using dried red choricero peppers. Use these instead of pimentón if you can get them. Soak the peppers in hot water for 30 minutes and scrape out the pulp following the directions on page 183.
If you can’t find good fresh tuna, you can prepare this recipe using salmon steaks.
1. In a deep cazuela, Dutch oven, or large, heavy pot, heat the olive oil over medium-high heat. Working in small batches, add the tuna and sear the cubes on all sides, just 1 minute or less per batch. Transfer to a platter.
2. Add the onion and cook until it begins to soften and turn pale, about 5 minutes. Add the garlic and bell pepper and cook until fragrant and softened, about 5 minutes. Add the tomatoes and cook until pulpy and darker red, about 10 minutes. Stir in the pimentón, season with salt, and add the potatoes. Turn to coat and cook for 1 minute. Add the bay leaf and pour in the stock. Bring to a boil.
3. Once the liquid begins to boil, reduce the heat to medium-low, and simmer until the potatoes are tender and the tip of a knife can easily penetrate them, 20 to 25 minutes, stirring from time to time. Add the tuna, cover the pot, and cook until the tuna is just opaque throughout, 3 to 5 minutes. Immediately remove the pot from the heat.
4. Let the stew rest for a few minutes, ladle it into bowls, and serve.