Soak the Cod– Cover salt cod with cold water and refrigerate for 24–48 hours, changing the water at least three times.
Cook & Flake– Drain and simmer in a saucepan with milk, thyme, bay leaf, garlic, and enough water to cover by 2 inches. Cook for 20 minutes until flaky. Remove, cool, and flake.
Cook Potatoes– Simmer potatoes in the same saucepan for 10 minutes until tender. Mash with 2 tbsp cooking liquid.
Mix & Chill– Sauté shallot and garlic in olive oil, then mix with potatoes, cod, cilantro, paprika, and egg yolk. Chill for 30 minutes.
Form & Coat– Shape into 1-tbsp balls. Dredge in flour, dip in beaten egg, and coat with breadcrumbs. Chill for 10 minutes.
Fry & Serve – Heat ½ inch oil in a skillet. Fry croquettes until golden, about 4 minutes. Drain on paper towels and serve with lemon wedges.