Monkfish liver is rarely seen outside of Japanese cuisine where it is known as ankimo. Those who have tasted its creamy decadence will understand why it's often referred to as "foie gras of the sea", although its flavor is more delicate with just a whisper of its oceanic origin in the aftertaste.
Ankimo is traditionally prepared as a torchon, much like foie. After removing the skin and veins, it is soaked in milk for 4 hours, then rinsed and brined in a solution of water/sake/mirin at a 5:3:1 ratio, with salt added at 3% of total weight, for 8 hours. The drained livers are compressed and rolled into a cylinder in a double layer of fine cheesecloth and the ends are tied. The cylinder is steamed over a 50/50 blend of water and sake until the core reaches 63C/145F, about 20 minutes for a 3" diameter torchon. Or it can be cooked in a 65C/149F water bath for 30 minutes. In either case, the torchon is allowed to rest in the refrigerator overnight before slicing.