Halibut with Fennel butter sauce

Rick Stein did this dish on telly on the weekend that made my mouth water. I think he was steaming trout over seaweed or something.. the fish bit is a blur because what mattered was the sauce! 
The halibut at the fishmongers looked really good and fresh and it went really well with the fennel as it can stand up to big flavour.


I steamed the halibut in paper parcels, greased with a little olive oil and pepper for 10 mins at 200C


Gradually melt a knob of butter in a pan and add chopped up fennel and cook until soft. 
Whizz up the fennel with a blender and add an egg yolk and seasoning. Return to pan and add a splash of white wine and a squeeze of lemon, salt and pepper. Finally add chopped fennel (the herb).