If you are not able to afford a whole salmon or you only want to serve 2 people, scale down the ingredients and use 2 salmon fillets.
A medium whole salmon (gutted)
1 medium onion (chopped)
1 bottle cava
5ml lemon juice
400ml creme fraiche
50g butter (chilled in small pieces)
Salt and pepper
1. Place the salmon into a well-buttered baking tin or dish with the chopped onion. Chop all but 12 of the mushrooms and add to the fish dish. Add the cava and season. Cook in a moderate oven for approx. 45-60 mins., basting 2 or 3 times.
2. Poach the reserved mushrooms for 5 mins. in water with the lemon juice. Drain.
3. Remove the salmon from the dish when cooked and reserve the liquid. Skin the fish, keep warm on a large serving dish and cover.
4. Strain the cooking liquid, reserving the mushrooms, onion and liquid. Reduce the liquid rapidly, add the creme fraiche and reduce again. Liquidise the mushrooms and onion and add to the reduced sauce. Stir over a moderate heat until thick. Whisk in the butter and test for seasoning.
5. Pour the sauce over the salmon and garnish with the reserved poached mushrooms.