Preheat the oven at 450°. Place aluminum foil over a cookie sheet and place the salmon in it. Sprinkle generously the salmon with salt and pepper. Place the cookie sheet in the hot oven, rack positioned in the center, and cook for 15 minutes.
Meanwhile puree with the help of a food processor the butter, parsley, lemon juice salt and pepper until smooth. Add the seasoning as needed.
When the salmon is ready serve with a teaspoon of the butter over it.
To store the butter, mound the butter on a sheet of plastic wrap. Fold the wrap over the mound then roll the butter back and forth under your palms to form a log shape. Roll up the log in the plastic and twist the ends to seal. Refrigerate the butter for up to a week, or freeze for a month or more.