Chef Joseba Arguiñano: "To give the sea bass more flavor, prepare this easy mushroom sauce"

Posted on 13 December 2025

Sea bass is one of the star dishes that we prepare in the oven. It doesn't require much skill, and if you find a good product, just add a little coarse salt and the work will be done by itself. Of course, you can always give it an extra touch to surprise diners at a dinner or delight yourself with a super simple sauce with only three ingredients. We have copied the recipe from chef Joseba Arguiñano who has shared in the 'Open Kitchen' program a tip that he always uses to give extra flavor to this simple recipe.

The sauce that the chef proposes has mushrooms as its main ingredient and the best of all is that it is super easy to make. So if you are not particularly handy with kitchen stoves, you can rest assured, because it is suitable even for the most beginners. Of course, the result and the flavor they provide to the sea bass is worthy of a classy restaurant and that is what truly interests us. We leave you the ingredients and the step by step so that you can start it from your home.

Mushroom sauce ingredients

  • 400 grams of mushrooms
  • Two large onions
  • 350 milliliters of cream

The step by step to achieve a result like Joseba Arguiñano

We begin the preparation by heating a large frying pan over low heat and adding four or five tablespoons of a good extra virgin olive oil, which will be our aromatic base for the sauce. While the oil is heating up, we peel the onions and cut them into thin julienne strips, so that they cook evenly. When the oil is ready, add the onion and let it sauté slowly for about ten minutes. In this way we get it to release its natural sugars and acquire that characteristic transparent tone.

As the onion cooks, we take the opportunity to clean the mushrooms well and cut them into not too thin slices, so that they retain their texture when sautéing them. When the onion is tender and slightly sweet, add the mushrooms to the pan. Next, we turn up the heat a notch and let everything cook well for eight to ten minutes, until they begin to brown.

We continue with our recipe and pour the liquid cream over the mixture, then stir gently so that it integrates with the vegetables. The sauce will begin to take on body little by little, achieving a silkier texture. Then we add salt and pepper to taste, and continue cooking over low heat for a few more minutes so that the mixture thickens even more in search of the perfect point to spread our sea bass.

When the sauce has reduced slightly and looks more or less homogeneous, remove it from the heat. It is now ready to become the ideal accompaniment to baked sea bass and give it that extra juiciness and a deeper flavor but without taking away its prominence. A simple, homemade sauce capable of elevating any fish in record time.

Other sea bass recipes that you can't miss

In addition to our classic grilled sea bass with this mushroom sauce, there are also other simple recipes that feature this delicious fish and that you can make from your kitchen. One of our favorites is the Donostiarra-style sea bass, where the touch of dried chilli and garlic is key to filling our dish with flavor. You can also opt for one more recipe premiumideal to treat yourself on a weekend night, and that is the sea bass in cider with clams, in fact we love this option because you can make it without turning on the oven.

Tricks to elevate your baked sea bass recipe to the next level

Our colleagues at DAP also use other key ingredients such as potatoes to give a more gourmet touch to your sea bass recipe. An especially simple proposal that can be a success together with the mushroom sauce. Another good option would be to add vegetables such as pepper and onion so that they are also cooked in the oven to give it extra flavor.

Olivia Thompson
Olivia Thompson
I’m Olivia Thompson, born and raised in Wellington, New Zealand. As a lifestyle and travel writer at Latitude Magazine, I’m passionate about uncovering stories that connect people with new experiences and perspectives. My goal is to inspire readers to see everyday life – and the world – with fresh eyes.

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