Place the salmon on a plate, defrost and acidify with a little lemon juice or vinegar (approx. 10-15 min.). Then cut into bite-sized pieces, pepper, salt and fry in hot oil.
Peel and dice the onions and sauté them in melted margarine in a separate pan. Add the flour and pour the cream on top. Then add the crème fraiche and season with pepper and dill. Pour in the broth and season to taste as required. Now add the salmon and let it steep for 10 minutes.
Cook the spaghetti according to the instructions on the packet. Then drain.