Preheat the oven to 180C and while it is heating up, get onto making the sauce.
Make the sauce first by getting the preserved lemon and removing all of the flesh, which you can then discard. Wash the skin a little and then place it in a small food processor. Add in the herbs and water and blend until smooth. Stir in the creme fraiche and set aside in the fridge to cool while you cook the salmon.
Place a large oven-proof pan over the high heat and add the olive oil. Season the fish with salt and pepper, giving more love to the skin side. Once the pan is hot, place the fish, skin-side down. Cook the fish for 2 minutes without touching it! Still without touching it, pop the fish into the oven and cook for a further 4 minutes. I always err on the side of caution and rather my salmon on the pink side so sometimes take it out sooner.
Using an oven mitt (I often forget) grab your pan out of the oven and place the salmon onto plates, skin side up. Spoon the cool lemony sauce on top and serve straight away with wilted spinach, sliced chilli and lemon wedges.