It’s incredible that salmon and blue mussels are two of our cheapest commodities.
Peel and chop finely the shallot and the fennel. Put the cuttings from the shallot and fennel in a pot with blue mussels, garlic and thyme.
If the mussels are fresh, you don’t need any liquid (if you aren’t quite sure, add a dash of water or white wine). Steam at a high temperature until most of the mussels have opened. Strain the stock through a fine-meshed sieve into a smaller pot.
Pick out the mussels (throw away the ones that didn’t open), and put aside.
Put finely chopped shallot and fennel in the pot and boil down until two thirds remain. Add capers, parsley and orange peel, and whisk in the butter.
Take the pot off the hotplate and add the blue mussels. Put aside and keep warm.
Steam the cabbage in a small pot with water and a tablespoon of butter. Pour out the water, season to taste with salt, and put aside.
Fry the salmon fillets in butter in a warm pan until it is golden and flakes when you put a fork in it.
Serve with cabbage and blue mussel butter.