Recipe from https://leitesculinaria.com/51785/blog-spanish-cod-fritters.html#
10 ounces salt cod
1 small onion, peeled and quartered
1 bay leaf
1 medium Yukon Gold potato (about 8 ounces), diced
2 garlic cloves, minced
2 tablespoons chopped flat-leaf parsley leaves
Salt and freshly ground black pepper
3/4 cup water
1 tablespoon olive oil
1/4 cup all-purpose flour
2 large eggs
Vegetable oil, for frying
Soak the salt cod
1. Rinse the cod well under running water to remove surface salt. Place the fish in a large bowl and cover with cold water by 2 inches. Stretch plastic wrap over the top, and refrigerate, changing the water several times until the cod is sufficiently desalted for you. Take a nibble—it’s perfectly safe to eat. If it’s too salty, change the water again, and let it sit for a few more hours. The process can take anywhere from 12 to 48 hours, depending on the type and size of the fillet. Above all, bear this in mind: You can always add back salt, but you can’t remove it from a finished dish.
Prepare the filling
2. Transfer the cod to a medium saucepan, add the onion and bay leaf, cover with fresh water by 2 inches, and bring to a gentle simmer over medium-low heat. Cook the salt cod until it flakes easily when poked with a fork, 10 to 12 minutes. Using a slotted spoon, transfer the cod to a plate, leaving the onion and bay leaf in the pan, and set aside until the fish is cool enough to handle.
3. Bring the water the salt cod was simmered in to a boil, drop in the potato, and cook until tender, about 10 minutes. Drain in a colander. Toss the bay leaf, keep the onion.
4. Dump the potato and onion into a bowl and mash them well. If the onion refuses to submit, really have at it, cutting it with a knife, if needed.
5. Remove any skin, bones, and miscellaneous bits and bobs from the cooled cod, then shred it. My grandmother vovó Costa used to dump the cod on one half of a tea towel, fold over the other half, and massage it, rubbing the towel back and forth with the heel of her hand until it left nothing but little clouds of finely shredded fish. The food processor does the same thing in 10 seconds. Sorry, vovó. Stir the cod shreds, garlic, and parsley into the potato mixture. Season with salt and pepper to taste. It’s not a bad idea to over-season a bit here, as the batter will tame the flavor some. Set aside.
Make the batter
6. Rinse the saucepan you’ve been using (a real one-pot meal), pour in the water and oil, and bring to a boil over medium heat. Shake in the flour slowly and stir with a wooden spoon to make a batter. It’ll be lumpy, but press on. A few more minutes and it’ll all work itself out.
7. Remove the pan from the heat and continue beating the batter for 2 to 3 minutes to cool it. Add the eggs one at a time, incorporating completely after each addition.
8. Add the cod mixture to the pan and stir to combine. It should be the consistency of a nice thick-enough-to-stand-your-spoon-up-in-it oatmeal. Let the batter cool to room temperature. This is the best part: If you wish, you can keep it for several hours and fry off the fritters whenever guests arrive, or when you’re in a white-hot state of hunger.
Fry the fritters
9. Heat 3 inches of the oil in a high-sided saucepan over medium-high heat until it reaches 350°F (177°C). Spoon out a rounded tablespoon or so of the batter, scrape it into the oil using another spoon—remember, irregular is better—and fry until golden brown and cooked through, 2 to 3 minutes. Drain on a brown paper bag (vovó always said paper towels make fried foods soft) and serve hot, hot, hot. Don’t give these puppies time to cool down and lose their crunch.