Preparation

• Thoroughly clean the rockfish under cold water, ensuring to remove any impurities. Place it in a large pot with cold water and let it simmer for 25 minutes over medium-high heat. Then, remove from heat and let it rest for 10 minutes. Strain the stock through a fine sieve, reserving it for later. Note: A store-bought fish stock can also be used as an alternative.
• Place the choricer pepper in a bowl and cover it with warm water. Allow it to soften for 30 minutes. Then, use a small spoon to scrape the pulp from the inside and set it aside. Note: If preferred, canned choricer pepper pulp can be purchased at the supermarket.
• Peel the potatoes and, using a knife, cut them into irregular chunks approximately 3 cm on each side. This will help thicken the marmitako during cooking.
• Blanch the tomatoes: bring a pot of water to a boil, submerge the tomatoes for 30 seconds, then immediately transfer them to a bowl with ice-cold water. Peel the tomatoes, remove the seeds, and chop the flesh into small pieces.
• Cut the tuna into cubes approximately 2 cm on each side to ensure even cooking.
• Place the tuna in a bowl and add a splash of brandy. Let it marinate for 30 minutes, stirring occasionally to ensure the brandy evenly coats the tuna.
• In a pan with a bit of oil, sauté the chopped Figueres onions over low heat for about 15 minutes until they begin to brown. Once they start to take on this color, add a tablespoon of sugar and continue cooking until they are fully caramelized, about 10 more minutes.
• Once the onions begin to turn translucent, add the chopped garlic and tomato. Stir well and let it cook for 1 hour over low heat, stirring occasionally to prevent sticking.
• Continue cooking the sofrito for a full hour, adjusting the heat if necessary to maintain a gentle simmer.
• When there are about 15 minutes left to finish the sofrito, incorporate the choricero pepper pulp and mix it well with the sofrito.
• Finely chop the spring onions and green peppers to achieve a homogeneous texture.
• In a large pot where we'll prepare the marmitako, heat a little oil and cook the spring onions and green peppers on low heat until they are well-caramelized, about 20 minutes.
• Once the spring onions and green peppers are caramelized, transfer them to the handheld blender container. Add the sauteed mixture from the pan and blend everything until you achieve a uniform and smooth texture.
• Pass the mixture through the handheld blender, and then strain it using a fine sieve to remove any lumps or impurities.
• Return the sauteed mixture to the pot and add the roughly broken potatoes. Cover the pot and let them cook for 5 minutes over medium heat.
• Pour the fish broth over the potatoes until they are completely covered. Add a pinch of black pepper and a little grated nutmeg. Increase the heat and let it boil for 10 minutes.
• Finely chop the parsley and set it aside to use at the end of the cooking process.
• When the potatoes are almost cooked, add the tuna cubes, the macerated cognac, and the chopped parsley. Stir gently to combine all the ingredients.
• Cover the pot and immediately turn off the heat to avoid overcooking the tuna.
• Let the marmitako rest with the pot covered for 5 minutes. The tuna will cook with the residual heat, achieving a tender and juicy texture.