Put the spring onions, lemon zest and juice, 4 tablespoons of the olive oil and the rocket into a food processor or blender. Blend together for a few seconds, then taste and season

Then heat the butter and the remaining tablespoon of olive oil in a large frying pan. Add 4 x 200 g (7 oz) fillets of wild Alaska halibut and cook for about 5 - 6 minutes, turning them once. Cook them for a little longer if they are quite thick, but avoid overcooking. The flesh should be opaque and should flake when tested with a fork

Serve with fresh baby vegetables and spoon over the relish.