Cod Croquettes: Recipe with Exact Proportions and Perfect Béchamel
Summary: Cod croquettes are one of those dishes that seem simple but hide a precise technique. The difference between croquettes that break open in the fryer, turn out pasty or have a gelatinous dough, and croquettes that are crispy on the outside, creamy on the inside, and have an intense cod flavor, lies in three points: the exact proportions of the béchamel, the cooking time of the mixture, and the oil temperature during frying.
This recipe comes from years of working with quality cod at the Mercat del Ninot in Barcelona. We've taken note of what goes wrong when they're made incorrectly and what makes a difference when they're made well. Here are all the key points, no beating around the bush.
The Cod: Which Part to Use and How to Prepare It
For croquettes, you don't need the noblest cuts of cod: trimmings, tails, and more irregular pieces are perfect. They are more economical and have the same flavor. The important thing is that they are good quality cod (Gadus morhua) and properly desalted.
You can also use leftover cod from another preparation, such as flakes from cod pil-pil or "a la vizcaína." Croquettes are, historically, a dish made from leftovers, and cod cooked in a previous stew can add even more flavor to the béchamel.
Cod options for croquettes:
- Desalted cod trimmings: the most economical and practical option. You can find them at any fishmonger or specialized stores like Bacalalo.com.
- Steamed cod: steam it for 5 minutes, let it cool, and shred it with your hands, removing bones and skin. Very simple.
- Leftover cod from another dish: make sure it doesn't have heavily spiced sauces that could alter the flavor of the béchamel.
Quantity: For 20 medium croquettes, you'll need about 250-300g of cod, already desalted, cooked, and shredded.
The Exact Proportions of the Béchamel
Here's the key that most recipes avoid giving precisely. A béchamel for croquettes is not the same as a béchamel for lasagna: it must be very thick, almost solid when cooled, to be able to shape the croquettes without them losing their form.
Proportions for 20 medium croquettes:
- 80g butter
- 80g wheat flour (the same amount by weight as butter)
- 700 ml whole milk (room temperature, not cold)
- 250-300g desalted, cooked, and shredded cod
- 1 small onion
- 2 cloves garlic (optional, but recommended)
- Freshly grated nutmeg
- Salt and white pepper
- Olive oil for sautéing the onion
For the coating:
- 2 beaten eggs
- Fine breadcrumbs (or panko for more texture)
- Flour for dredging (optional, but helps the coating not fall off)
For frying:
- Mild olive oil or sunflower oil for frying (plenty, at least 1 liter)
Step-by-Step Preparation of the Mixture
Step 1: Prepare the cod
If you're starting with salt cod, desalt it for 24-36 hours in cold water, changing the water every 8-12 hours. For trimmings or small pieces, 24 hours is usually enough.
Once desalted, steam the cod for 5 minutes (or simmer gently in a pot with a little water for 4-5 minutes). Let it cool completely. Carefully remove all bones: run your fingers through the shredded flesh to make sure none remain. Also remove the skin if it has any. Set aside.
Step 2: Sauté the onion and garlic
In a wide, heavy-bottomed pot (the same one where you'll make the béchamel), sauté the very finely chopped onion in 2-3 tablespoons of olive oil over low heat for 12-15 minutes. The onion should become completely transparent and very soft, without browning. Add the minced garlic and cook for 2 more minutes. If the onion caramelizes too much, the color of the béchamel will be brown instead of white.
Step 3: The roux (the béchamel base)
This is the most technical part of the recipe. Add the butter to the pot with the sautéed onion and let it melt over medium heat. When the butter is liquid but not browned, add all the flour at once. Stir vigorously with a whisk or wooden spoon for 2-3 minutes. The goal is to cook the flour so the béchamel doesn't taste raw. The roux should be a pale cream color, not dark.
Key: if the roux smells pleasantly toasted (like butter cookies), it's perfect. If it smells burnt, start over.
Step 4: Incorporate the milk
Add the warm milk gradually, stirring continuously with the whisk over medium-high heat. First, add 200 ml and stir vigorously to prevent lumps. Once fully incorporated, add another 200 ml and repeat. Continue until all the milk is incorporated.
Once all the milk is incorporated, cook the béchamel over medium-low heat, stirring constantly for 15-20 minutes. The mixture is ready when it cleanly separates from the sides of the pot and leaves a residue on the bottom. Test with a spoon: if the mixture sticks and takes time to fall off, it has the right consistency.
Step 5: Incorporate the cod and aromatics
Add the shredded cod to the béchamel and mix well. Season with freshly grated nutmeg, white pepper, and salt (be careful, the cod already has residual salt). If you want to intensify the cod flavor, add a tablespoon of oil where you previously candied garlic.
Cook for 5 more minutes over low heat, stirring constantly, so the cod is fully integrated with the béchamel.
Step 6: Rest the mixture (essential)
Spread the mixture in a flat dish or tray, cover it with cling film directly on the surface (this prevents a crust from forming), and let it cool at room temperature for 30 minutes. Then refrigerate for a minimum of 2 hours, although ideally, leave it overnight.
Why resting is essential: hot dough is too soft to shape croquettes. As it cools, the gelatinization of the starch makes it firm and manageable. Dough that hasn't rested enough will stick to your hands, the croquettes won't hold their shape, and they'll break open when fried.
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Shape, Coat, and Fry
Shaping the croquettes
Take the mixture out of the fridge. With an ice cream scoop or two regular spoons, take portions of about 40-50g (the size of a large walnut). Shape them into cylinders or ovals with floured hands or using plastic wrap. If the mixture sticks to your hands too much, wet your hands with cold water between croquettes.
Tip for uniform croquettes: use a piping bag without a nozzle or a zip-top bag. Put the mixture in, seal, and cut the corner. Extrude cylinders of mixture onto a floured surface and cut them with a knife. This way, all croquettes will be the same size and will fry evenly.
The three-step coating
The order is crucial: flour, egg, breadcrumbs. Don't change it.
- Flour: roll each croquette in flour and shake off the excess. This layer helps the egg adhere and prevents the coating from falling off in the oil.
- Beaten egg: dip the floured croquette into the beaten egg, draining off any excess.
- Breadcrumbs: roll the croquette in breadcrumbs, pressing lightly to ensure they adhere well. For a thicker, crunchier crust, you can repeat the egg and breadcrumb step a second time (double coating).
Once coated, place the croquettes on a tray and put them back in the fridge for 30 minutes before frying. The cold helps the coating adhere better and prevents the croquette from breaking open in the oil.
Frying: temperature and technique
This is the point where most croquettes go wrong. Oil temperature is crucial:
- Ideal temperature: 175-180°C (347-356°F). Below 170°C (338°F), croquettes absorb too much oil and become greasy. Above 190°C (374°F), the outside burns before the inside heats up.
- Amount of oil: abundant. Croquettes should float and be at least half-submerged. In a shallow pan with little oil, croquettes rest on the bottom, the heat is uneven, and they are more likely to break open.
- Quantity per batch: fry only a few croquettes at a time (maximum 4-5 in a medium pan). If you add too many, the oil temperature drops sharply, and the croquettes will cook rather than fry.
- Time: 2-3 minutes per side, turning carefully to brown evenly. The total should not exceed 5-6 minutes.
How to know if the oil is at the correct temperature without a thermometer: drop a small piece of bread into it. If it bubbles actively and browns in 20-25 seconds, the oil is ready.
Why Croquettes Break Open and How to Prevent It
Croquettes break open for four main reasons, all of which are preventable:
- Mixture too soft: the béchamel didn't have enough consistency or didn't rest long enough in the cold. The solution is to respect the proportions and resting time.
- Deficient coating: if the coating has gaps or isn't well adhered, internal steam breaks the crust. Make sure the coating covers the entire croquette without gaps.
- Oil too cold: if the oil isn't hot enough, the croquette stays in the oil too long before the coating seals, and moisture from the inside breaks it open.
- Croquettes not cold before frying: if the croquettes are at room temperature or warm, the inside heats up very quickly and generates steam that pushes outwards. Always fry them cold, directly from the fridge or freezer.
Freezing: How to Do It Right
Cod croquettes freeze perfectly. The correct method is to freeze them once coated, before frying, not after. Place them on a tray without touching each other and put them in the freezer for 2 hours. Once individually frozen, transfer them to a freezer bag where they can be kept for up to 3 months.
To fry them from frozen, there's no need to thaw: go directly from the freezer to oil at 170°C (a little lower than for fresh ones so the inside heats through properly). Frying time will be slightly longer: 4-5 minutes per side.
Recipe Variations
Cod croquettes with caramelized onion
Replace the regular onion sauté with onion caramelized slowly for 40 minutes over very low heat with a little sugar. The sweetness of the onion contrasts perfectly with the salty taste of the cod. They are more complex but exceptional.
With roasted red pepper
Add a roasted and peeled red pepper, cut into very fine brunoise, to the mixture. It adds sweetness, color, and a smoky touch. Ideal if the cod comes from a Rioja-style preparation.
With alioli for dipping
Cod croquettes pair perfectly with alioli (not mayonnaise with garlic: real alioli, an emulsion of garlic and oil). For lovers of intense flavors, also add a squeeze of lemon to the alioli. Serve in a separate bowl for dipping.
At Bacalalo.com you'll find desalted cod trimmings and tails at a very competitive price, perfect for making croquettes without the cost of the main ingredient limiting your quantity. Quality cod makes a difference even in croquettes: cod with good natural flavor makes a more intense and tasty béchamel.
Frequently Asked Questions about Cod Croquettes
Why does my béchamel have lumps?
Lumps in béchamel form when the roux and milk don't integrate well. The most common causes are: adding cold milk all at once (which solidifies the roux abruptly), not stirring vigorously enough, or not using a whisk. The solution is to add warm milk in thin streams while stirring continuously in a circular motion. If you already have lumps, pass the béchamel through a food mill or use a hand blender before adding the cod.
How long can the mixture stay in the fridge?
The croquette mixture keeps perfectly for 48 hours in the fridge, well covered (with cling film directly on the surface to prevent it from drying out). Ideally, prepare it the night before. If you need more time, you can freeze the shaped and coated mixture before frying: it keeps for up to 3 months in the freezer.
Can I use semi-skimmed or skimmed milk?
It is not recommended. The fat in whole milk is what gives béchamel its creaminess. With semi-skimmed milk, the result is acceptable but drier. With skimmed milk, the béchamel will be pasty and lack unctuousness. If you're looking for a lighter version, reduce the amount of butter in the roux (use 60g instead of 80g), but don't change the milk.
Panko or regular breadcrumbs?
It depends on the result you're looking for. Fine breadcrumbs create a more homogeneous and compact crust, more similar to classic bar croquettes. Japanese panko creates a crunchier, more irregular crust with more texture. If you've never tried panko for croquettes, we recommend it: the difference in texture is noticeable. You can mix 50% panko and 50% fine breadcrumbs to combine the best of both.
What exact temperature should croquettes be fried at?
175-180°C (347-356°F) is the ideal temperature. Above 185°C (365°F), the outside burns before the inside heats evenly. Below 170°C (338°F), croquettes absorb too much oil, become greasy, and are more likely to break open. If you don't have a kitchen thermometer, the breadcrumbs that fall into the oil should bubble actively and brown in 20-25 seconds. Many home fryers have a 180°C (356°F) setting which is perfect.
Can I make gluten-free croquettes?
Yes. Replace wheat flour with cornstarch (corn flour) in the same proportion and use gluten-free breadcrumbs for the coating. Cornstarch béchamel has a slightly different texture (more gelatinous, less lumpy), but it works well for croquettes. Also, ensure that the cod you use has not been processed with flours (simple fillets don't have this problem, but some prepared ones do).
How many croquettes does this recipe yield?
With 700 ml of milk, 80g of butter, 80g of flour, and 250-300g of cod, you'll get between 18 and 22 medium croquettes (about 40-50g each) depending on the size you make them. If you make them smaller (appetizer size, 25-30g), you can get up to 30. If you like them large and generous (60-70g), you'll get about 15.
How do I know if the cod is properly desalted for croquettes?
Taste a small piece of raw cod before cooking it. It should taste like normal food with its saltiness, it should not be excessively salty. If after 24 hours of desalting it is still very salty, change the water and leave it for 12 more hours. For croquettes, it is especially important not to over-salt: since the cod is mixed with the béchamel and concentrates when cooked, the final saltiness can be more intense than expected. With already desalted fillets from Bacalalo.com this step is not necessary: the desalting is factory controlled.
Can I add other ingredients to the mixture?
Absolutely. Cod croquettes allow for many combinations. The most popular are: cod with shrimp (add 100g of cooked and chopped shrimp along with the cod), cod with drained and sautéed spinach, and cod with very finely sautéed leek instead of onion. You can also add a splash of txakoli or white wine to the sauté for more depth. The key is that the added ingredients are very dry so as not to add extra moisture to the mixture.
