Rehydrate the salted codfish by covering it in a dish filled with clean cold water 4 different times, at 12-hour intervals.
In a large skillet, sauté the onion with the canola oil and smoked paprika at low heat.
Once the onion is soft, add the codfish and the flour.
Cook the flour through to form a homogeneous dough.
Bring the skillet to medium heat, and slowly add the milk.
Stir the mixture until the desired texture is obtained, then add the spinach.
Add more salt and paprika.
Remove from heat and cover with plastic wrap. Ensure the plastic touches the dough to preserve its moisture.
Leave to cool overnight.
Pour the black Hojiblanca olives into a blender. Pulse until a purée is obtained.
Add the anchovies and lemon juice.
Incorporate the cilantro and pepper to taste.
The next day, beat the eggs in one bowl, and prepare another bowl with the breadcrumbs.
Shape the croquettes to your liking. Roll them in flour, pass them through the eggs and coat them with the breadcrumbs.
Arrange them on a tray and refrigerate overnight until ready to cook.
In a fryer or small pot, heat the canola oil to 350°F.
Cook the croquettes for about 1 minute until they become golden brown.
Place them on paper toweling to absorb any oil excess.
Arm yourself with a glass of red wine and good company before serving.