Chilean Sea Bass with Lemon Butter Sauce

Ingredients

Lemon Butter Sauce

Butter is the heart of this sauce, bringing creaminess and depth to the mix. Opt for unsalted butter so you have better control over the amount of salt in your sauce. Quality matters here – go for a high-fat European-style butter if possible, as its richer flavor will make a noticeable difference.

Want a clear sauce without the milk solids? Swap in ghee, which is clarified butter. Ghee has a robust, nutty flavor that pairs perfectly with the zingy notes of lemon, giving your sauce a slightly caramelized edge. Whichever you choose, make sure it’s cold and cubed before adding it to your sauce to help emulsify the ingredients.

Fresh lemon juice makes the sauce pop. Bottled lemon juice just can’t cut it; it lacks the vibrant acidity and clean, crisp flavor of a freshly squeezed lemon.

Lemon juice provides the perfect counterpoint to the butter’s richness. This balance of fat and acid keeps the sauce from tasting too heavy, creating a light, refreshing finish that complements Chilean sea bass beautifully. As an added tip, roll the lemon under your palm before cutting it open to coax out more juice.

Fresh thyme, with its earthy, slightly peppery notes, is a classic choice that pairs effortlessly with both butter and lemon.

Creamy Mashed Cauliflower

• Head of Cauliflower – I used purple for added color BUT, the lemon in the sauce causes the cauliflower to turn hot pink! It does not change the taste at all, and adds more color to the dish.
• Heavy Cream or Canned Coconut Milk – Adds a rich, creamy texture. Substitute coconut milk for dairy-free.
• Chicken Broth – Adds additional flavor and keeps the dish from being too rich from additional cream.
• Garlic Powder, Kosher Salt, and Black Pepper

Check out the printable recipe card below for the complete recipe and detailed instructions.

How to Make Chilean Sea Bass with Lemon Butter Sauce

Creamy Mashed Cauliflower

Chop the cauliflower into florets and steam for 10-12 minutes, or until fork-tender.

Transfer the cooked cauliflower to a large bowl. Add butter, minced garlic, chicken broth, and heavy cream. Puree with a stick blender until smooth, adjusting the cream for your desired consistency. Set aside and keep warm until ready to serve.

Butter Poached Chilean Sea Bass

Pat the fillets dry with a paper towel. Lightly season both sides of the fish with salt and freshly cracked black pepper.

Use a heavy-bottomed skillet (cast iron or stainless steel works best) and add 7 tablespoons of ghee/butter, minced garlic, and fresh thyme sprig. Heat over medium-low heat until it’s lightly bubbling.

Carefully place the fish in the pan, then swirl the pan around so the butter coats the top of each filet. I like to scoop and pour the butter over the top of the fish with a large spoon to help it cook from the top as well.

Allow the fish to poach slowly until it becomes opaque, and it reaches an internal temperature of 145°F (63°C), about 3-5 minutes. Continue swirling the butter frequently to prevent it from burning. Thicker fillets may be carefully flipped over to finish cooking

Remove fish and divide between two plates, placing sea bass on top of mashed cauliflower. Stir lemon juice into butter in skillet, then spoon lemon butter sauce over the fish. Serve immediately.

Dim the lights, light some candles, and put on a playlist of soft music to set the mood to enjoy this simple and delicious meal.

How long should I poach the Chilean Sea Bass?

Poach the fish for about 6-15 minutes, depending on the thickness of the fillets. The fish should be opaque and flake easily with a fork when done. If the pieces are different thicknesses like mine, pull out the thinner pieces and set aside until the rest are cooked.

What temperature should I poach the fish at?

Poaching is typically done at a low temperature, around 160°F to 180°F (70°C to 82°C). The liquid should be hot but not boiling.

Can I use other herbs besides thyme?

Yes, you can substitute or add other herbs such as dill, parsley, or tarragon, depending on your flavor preference.

What can I serve with poached Chilean Sea Bass?

If you prefer to not serve with mashed cauliflower, it pairs well with a variety of sides, such as steamed broccoli or asparagus, classic rice pilaf, or roasted garlic mashed potatoes.

How do I know when the fish is done?

The fish should be opaque and easily flake with a fork. You can also use a food thermometer to check that it has reached an internal temperature of 145°F (63°C).

Can I make this dish ahead of time?

While poached fish is best served fresh, you can poach it ahead of time and store it in the refrigerator in an airtight container. Reheat gently before serving. Store and reheat fish and mashed cauliflower separately.

Is Chilean Sea Bass sustainable?

It’s important to check for sustainable sourcing, as some fisheries may have overfishing concerns. Look for certifications like the Marine Stewardship Council (MSC) label.