For the sauce, finely chop the shallot and heat it in a saucepan with white wine over medium heat. Use just enough wine to cover the shallots.
Season the fish with salt and mild chilli, then cook it in a pan with olive oil.
Add the cream and the cubes of butter to the white wine. Whisk the sauce a little, it should still stay fairly loose.
Squeeze half a lemon into the sauce.
Add the herbs.
Once the fish is cooked you can plate up.