Cod with Creamy Potato Mousseline and Black Sauce

Recipe for a slow cooked cod in nut butter with creamy potato mousseline, crisp glassworts and hot black sauce

The gentle cooking of the fish in nut butter gives it a special creamy mouthfeel and a nutty flavour. The skin of the fish is really soft and pleasant to eat. Fluffy potato mousseline and the crisp, salty glassworts are a nice combination. The hot black sauce gives the desired spice to the dish. A wonderful fish course on your menu.

110 minutes

For 10 people

INGREDIENTS (10 portions)

For the Cod and Nut Butter
1.5 kg cod, scaled
750 g Oldenburger Butter, unsalted
pinch of sea salt

For the Potato Mousseline
2 kg floury potatoes
200 ml Oldenburger Fullcream Milk, 3.5% fat
150 ml Oldenburger Whipping Cream, 30% fat
200 g Oldenburger Butter, unsalted
1 tsp nutmeg, grated
pinch of salt
100 g breadcrumbs

For the Black Sauce
4 onions
300 ml seafood fond
20 g chipotle en adobo (see chef to chef tips)
5 g squid ink
20 g Oldenburger Butter, unsalted
1 tbsp brown sugar

For the Glasswort
500 g glassworts (see chef to chef tips)
seafood fond
20 g Oldenburger Butter, unsalted


For lunch or dinner, this menu looks impressive and is simply delicious. A fish dish for every day!

Peel the onions and cut into chunks. Bring a pot with salty water to the boil and add the potatoes. Pour the Oldenburger Fullcream Milk and the Oldenburger Whipping Cream in a pot and let it simmer. Cut the fish filet into the desired portions and carefully make cuts in the skin. Wash the algae (glassworts) and pat dry. Roast the breadcrumbs in a hot pan until golden brown and set aside.

The Nut Butter and Cod
Heat the Oldenburger Butter in a pot at high heat. When the butter begins to simmer, the whey will separate from the fat. Skim the whey gradually off, using a skimmer. This will result in a clear butter. It turns brown after a few minutes and develops the desired nutty aroma. When the Oldenburger Butter has turned dark brown and the whey has been completely removed, throw a sieve with a cloth.
Take a tray and fill the nut butter in and heat it to 68 °C. When it has reached the temperature, place the cod on the tray and let it slowly cook for about 20 minutes.

The Potato Mousseline
Peel the cooked potatoes and press them through a potato press. Add the room tempered Oldenburger Butter plus the mixture of warm Oldenburger Fullcream Milk and Oldenburger Whipping Cream. Season with salt and nutmeg and mix it well. If you want it super soft, strain the puree through a sieve. Take 5 spoons of the mash and set aside.

The Black Sauce
Heat the Oldenburger Butter in a pot, add the onions and let it simmer for approx. 20 minutes medium heat. Pour in the ‘chipotle en adobo’ and the seafood fond and let it simmer for another 10 minutes. Put the mixture into a blender, add the ink and mix to a smooth consistency. Season with brown sugar. Pour the sauce into a squeeze bottle, this will help you to make nice dots on the plate.

The Glasswort
Pour 5 spoons of potato mash and a handful of glassworts with some seafood fond into the blender and mix until smooth. Heat some butter in a pan, add seafood fond and put the rest of the glassworts in and fry them up.  

The Final Touch
For serving, use a square food ring to bring the potato mousseline into shape and remove the food ring afterwards. Sprinkle some roasted breadcrumbs around if you like it more fancy.


01. Butter is a natural product and adds a beautiful flavour to any product. It also acts as a flavour enhancer and brings out flavours in any dish.

03. Chipotle is a smoke-dried ripe jalapeño chili pepper used for seasoning. It is a chili used primarily in Mexican and Mexican-inspired cuisines. Chipotle in adobo consists of chipotle chilli peppers and is marinated with a rich, tasty tomato sauce.

02. If you like it fancy, try to roast some panko breadcrumbs and put them around and on the potato mash, this gives a nice extra crunch and looks impressive.

04. Glassworts are plants that thrive in saline environments, such as seacoasts and salt marshes.

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