Cullen is a Scottish fishing village, and a "skink" is a smoked ham hock, implying a history to the dish, but it's also an insult to Cullen. In turn, they have nothing good to say about the village of Findon, which is where Finnan Haddie originates. (Scotland has gone a bit downhill since Mel Gibson was hung, drawn, and quartered.)
This is my much-simplified version of the Saveur recipe. They faff on about mashing the spuds, piping them into rosettes, then toasting before floating on top of the soup, which adds nothing except complication: it's a rustic recipe and should be kept that way.
1 lb. smoked haddock (best) or any other smoked fish except salmon, which is just too polite for this recipe
2 C milk
2 C + heavy cream
1 Yukon Gold potato, or any waxy potato that holds its shape well.
1 large yellow onion, peeled and finely chopped
Freshly ground black pepper, salt
2 scallions, greens only, finely chopped
1/2 bunch parsley, finely chopped
Remove any skin and bones from fish and set aside. Trim off ragged edges of fish and add to skin and bones. Cut the fish into 1/4" cubes.
Peel the spud and throw away all that flavour if you insist, but I much prefer to just scrub them. Cut into 1/4" cubes, spread them on the microwave turntable and zap them for 5-6 minutes. This gets them cooked, and also dries their outsides so you can quickly brown them, duplicating what Saveur was after for no effort at all.
Scald milk and 2 C of the cream together in a medium pot over medium-high heat. Remove pot from heat, add fish skin, any bones, scraps of fish, and trimmings, and let steep until cream mixture is cool, about 30 minutes. (I always have shrimp heads/shells in the freezer, and they're a nice addition here.) If you want to amp up the stock flavour more, add a little Better 'n Bullion Fish Base
, which is basically cod and (too much) salt, and is excellent.
Heat a wide medium pot over medium-low heat. Add butter and potatoes, and fry until light gold, set aside. Add onion to pan and gently fry until softened but not browned. Add the spud and fish cubes. Strain cooled cream mixture into pot, discarding solids, and simmer soup over medium heat for 5-10 minutes. Season to taste with salt and pepper.
Serve, supplying chopped parsley/scallions for sprinkling.