Cook the pasta according to packet instructions. Put the broccoli in a steamer and steam over the cooking pasta (or cook the broccoli separately if you prefer).
Heat the oil in a frying pan over a low heat and cook the onion and garlic for 5-10 mins until soft. Turn the heat down to low and stir in the crème fraîche, lemon zest and juice and then slowly pour in the pasta water whisking as you pour. Mix until everything is combined and add the broccoli. Season well.
Add the salmon followed by the pasta and toss until the pasta is coated by the sauce. Serve topped with chopped chives and dill.
Nutrition information is an estimate and will vary depending on the ingredients used.