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).