Heat 1 tablespoon of the butter in a frying pan over medium heat. Add the salmon fillets and cook for 15 minutes turning over after 7 minutes.
In a large saucepan heat 1 tablespoon of the butter and cook shallots over medium heat for 5 minutes. Add the spinach and cook until the water has completely evaporated. Add the creme fraiche and reduce until thickened.
Place the salmon fillets on a serving platter with a side of spinach and sprinkle with lemon juice. Sprinkle with herbs and garnish with lemon slices. Serve with spinach.