Melt-In-Your-Mouth Butter Poached Cod
When you’re looking for a refined yet effortless dinner, butter poached cod is the perfect choice. This dish is rich, silky, and infused with delicate flavors, making it ideal for a weeknight treat or a romantic date night at home.
Fresh cod fillets gently poach in clarified butter, absorbing the aromatics of fresh tarragon, garlic, and a hint of chili for a subtle kick. The result? A melt-in-your-mouth, fork-tender fish that is both light and luxurious.
But what truly elevates this dish is the homemade tarragon aioli. Creamy, herbaceous, and tangy, it complements the delicate cod beautifully, adding a finishing touch that makes every bite unforgettable.
Be sure to check out more of my easy seafood recipes, like Parmesan-crusted cod with tartar sauce, Mediterranean baked cod, or my kids’ personal favorite, this baked cod with Rtiz crackers!
Why You’ll Love This Recipe
- Rich and Silky Texture – Poaching cod in butter ensures it stays incredibly moist and tender.
- Refined Yet Simple – This dish feels restaurant-quality but is easy to make at home.
- Versatile and Customizable – Swap tarragon for parsley, oregano, or chives if preferred.
Ingredients Needed
For the poached cod:
- 1½ lbs fresh cod fillets
- 1 cup unsalted butter (for poaching)
- 3 cloves garlic, smashed
- 1 sprig fresh tarragon
- 1 small red or green chili, thinly sliced (optional)
- Kosher salt, to taste
- Freshly ground black pepper, to taste
For the tarragon aioli, you’ll need: an egg, a garlic clove, fresh lemon juice, canola oil, extra virgin olive oil, kosher salt, black pepper, and fresh tarragon.
How To Butter Poached Cod
Step 1: Make Clarified Butter
Clarified butter is essential for poaching because it prevents burning and provides a pure, buttery flavor.
- Place butter in a saucepan over low heat until melted.
- Allow it to cook gently until the milk solids rise to the top.
- Skim off the foam and discard.
- Strain through a fine-mesh sieve if desired for a perfectly clear butter base.
Step 2: Poach The Cod
- Season cod fillets lightly with salt and pepper.
- In a large pan, heat the clarified butter over low heat, adding garlic, tarragon, and chili (if using).
- Once warm but not bubbling, carefully add the cod fillets.
- Cover and poach for 6-10 minutes, depending on thickness. The fish is ready when it reaches an internal temperature of 120°F and flakes easily.
- Use a slotted spatula to transfer the fish to a plate, being mindful of its delicate texture.
It’s okay if the cooked cod pieces fall apart. This might happen because it’s so tender. It’s all going to the same place anyway! For another incredibly tender melt-in-your-mouth recipe, try this cod fillet roasted with white wine next!
How To Make Tarragon Aioli
- In a food processor, combine the egg, minced garlic, and lemon juice.
- With the motor running, slowly stream in the canola oil until thick and emulsified, about 30 seconds to 1 minute.
- Scrape down the sides, then slowly whisk in the olive oil.
- Stir in chopped tarragon, salt, and pepper.
Don’t love tarragon? You could replace it with any other fresh herb you love; oregano or parsley are great options. But tarragon and fish go so well together. I highly recommend!
Tarragon aioli can be made a day in advance and stored in the fridge.
Storage & Reheating
- Storage: Leftover poached cod can be stored in an airtight container in the refrigerator for up to 2 days.
- Reheating: Warm gently in a pan over low heat with a bit of reserved clarified butter to prevent drying out.
- Freezing: Poached cod is best enjoyed fresh, but it can be frozen in an airtight container for up to 1 month. Thaw in the refrigerator before reheating.
Serving Suggestions
- Creamy Mashed Potatoes – The luxurious texture pairs perfectly with buttery mashed potatoes.
- Crisp Roasted Vegetables – Try oven-roasted broccoli or Brussels sprouts for a contrast in texture.
- Fresh Green Salad – A simple arugula salad with lemon vinaigrette balances the richness of
This butter poached cod recipe with tarragon aioli is a simple yet stunning dish that delivers restaurant-quality flavors at home. If you make this recipe, be sure to leave a review and let us know how it turned out!
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Butter Poached Cod with Tarragon Aioli
Ingredients
For the poached fish
- 2 lbs butter unsalted
- 1 ½ lb cod
- 3 sprigs fresh tarragon
- 2 cloves garlic smashed
- 1 red or green chili thinly sliced, optional
- 1 tsp Kosher salt
- ¼ tsp freshly ground black pepper
- Chives finely chopped, for serving
- Sea salt for serving
For the tarragon aioli
- 1 large egg
- 1 clove garlic minced
- 4 tsp fresh lemon juice
- ½ cup canola oil
- ½ cup extra virgin olive oil
- ½ tsp Kosher salt
- ⅛ tsp freshly ground black pepper
- 2 Tbsp fresh tarragon finely chopped
Instructions
- Make clarified butter. Place 2 lbs butter in a large skillet or sauce pan over low heat until melted. Allow to cook until the milk solids float to the top. Once the butter stops bubbling, use a spoon to skin the foam off the top of the butter, then discard. What remains is clarified butter!
- Sauté the aromatics. Add 3 sprigs tarragon, garlic, and sliced chili (if using) to clarified butter, then warm over medium heat. Make sure the skillet is large enough to fit all pieces of cod in an even layer.
- Poach the fish. Cut cod into 3 or 4 roughly equal sized pieces. Season cod on both sides with 1 tsp Kosher salt and ¼ tsp black pepper. Add the cod to the warm butter, then cover and poach until cooked through, about 6-10 minutes. Thinner pieces of cod (the tail) will finish cooking before the tenderloin (thicker piece). You can carefully remove the cooked cod with a large spatula or spoon and transfer to a plate or serving platter while the remaining pieces cook through. Meanwhile, make the tarragon aioli.
- Make the tarragon aioli. Place the egg, minced garlic, and 4 tsp lemon juice into the bowl of a food processor fitted with blade attachment. With the motor running, slowly stream in ½ cup canola oil until the sauce has thickened up, about 30 seconds – 1 minute. Scrape down the sides as needed, process once more, then transfer to a bowl.
- Finish with olive oil. Slowly stream in ½ cup extra virgin olive oil while whisking constantly until incorporated and thick.
- Finish with fresh herbs. Add chopped 2 Tbsp tarragon, ½ tsp salt, and ⅛ tsp pepper, then mix to combine. Serve over poached cod. Garnish with chives, a tiny sprinkle of flaky sea salt, and some freshly cracked black pepper.
Notes
- When making clarified butter, you will lose about 25% of the volume that you begin with. It’s easy to scale up or scale down the quantity you make, as needed. Clarified butter can be used in any recipe that calls for butter, and is especially delicious served alongside seafood, such as lobster or crab, mixed in with scrambled eggs, or with any vegetable side dish.
- When stored properly in a sealed, airtight container, clarified butter will keep for up to 6 months in a refrigerator.
- To make aioli with an immersion blender: place egg, garlic, and lemon juice in a glass or cup large enough to fit the head of the immersion blender. Add canola oil, then place the immersion blender in and turn on. Process until aioli forms, lifting and tilting the head of the blender slightly so that the sauce is well incorporated. Transfer to a bowl, then continue with instructions to stream in, whisk olive oil, and then add tarragon.
Tell us about the red cabbage? shown in the photo? seared? grilled?
What is the advantage in clarifying the butter beforehand?
Thanks+
Hi Mike! That’s actually a charred radicchio salad. If you’re not familiar with radicchio, it is quite bitter. You can grab the recipe here, which is paired with balsamic (for sweetness), honey, lemon, and cheese.
When you remove the milk solids and water (from clarifying butter), you are left with only the butterfat. This has a higher smoke point, meaning that it is less likely to burn. If you do not clarify the butter first, the milk solids will cause it to burn. Hope this helps! xo, Ari
Do you throw away the leftover clarified butter after using it or is it reusable?
Cheers,
H
Hi Hugo! You can definitely save the oil to use again in a similar preparation. I’d stick to using it with other seafood dishes because of the flavor — it’ll infuse as it cooks. Store in an airtight container in the fridge and use within a month. It’ll congeal, but can be melted or allowed to come to room temperature to soften, as needed. Hope this helps! xp, Ari