Melt the butter in a large, wide-based pan over a gentle heat.
Add the shallots and fennel and fry over a high heat for about 2–3 minutes.
Lower the heat, cover the pan with a lid and continue to cook for about 8–10 minutes until tender.
Pour in the wine and boil to reduce by half.
Stir in the crème fraîche and bring to the boil.
Season with salt and pepper.
Place the salmon strips in a single layer in the sauce.
Cover the pan and simmer gently for about 4 minutes until the salmon is nearly cooked.
Add the peas, pushing them under the sauce, and continue to cook for about 3 minutes.
Stir in the lemon juice, check the seasoning and sprinkle with parsley.
Serve with the sauce and some rice, mashed potato, grains or crusty bread.
