Place the cut up liver in a bowl, just cover with water and 1 to 2 tablespoons of vinegar, Leave to soak for about 1 hour.
Remove the peel and white pith of the blood oranges, and separate into segments. Place a small bowl under to catch any juice that falls.Toss watercress, blood orange segments, fennel and nuts in a large bowl . Remove the Raspberries and put into the salad.
Whisk molasses, caught juice and oil. Season to taste with salt and pepper.
Melt butter in a frying pan over medium-high heat. Season livers with salt and pepper, and cook until browned but still pink in the centre. Toss with salad and pomegranate dressing.