Prepare all ingredients. Peel and cube potatoes, keep them in cold water till cooking. Wash and slice thinly leeks. Separate filet, bones, and skin of smoked wWhite fish tail. I prefer the tail for more skin and bones, which are used to make smoked fish stock.
Cover fish skin and bones with 6 cups of cold water. Bring to boil on high heat, reduce to low, and simmer for 20 minutes. Strain the stock. Discard fish skin and bones.
While fish stock is cooking, melt butter on medium heat, add leeks, and cook them till soft and fragrant. Do not brown them. Add potatoes and saute them for 4-5 minutes. Add smoked fish stock, season with salt and black pepper, add bay leaf, and simmer on low heat for 20 minutes, covered with a lid.
Add Tactical Nuclear Penguin. Adjust the taste. Add half of scallions, parsley, and cream. Turn off the heat.
Serve hot, sprinkled with more scallions and parsley.