You CAN clarify salted butter.
More Info: Though the clarification process will remove some of the salt it will not remove it all so additional salt will be added to the recipe.
What Is Clarified Butter?
Clarified butter is butter that has had the water and milk solids removed. Clarified butters are called for in recipes that require high temperatures as the removal of the water and milk solids keeps it from burning so quickly. The removal of the milk solids also helps it to keep longer.
To make one cup of clarified butter you will need one and one-quarter cups of butter. Depending on how are using the butter you may want to choose unsalted butter as clarifying will remove the salt, but not all of it so additional salt will be added to the recipe. Choose a heavy pan that heats evenly as you need to be cautious not to burn or overcook the butter as it is melting.
Cut the stick of butter into smaller sections for faster melting and place in the saucepan over a very low heat setting.
Allow the butter to melt without stirring or disturbing it.
Continue to slow heat the butter past its melting point until you can see three distinct layers have formed-foam, liquid, and milk solids.
Extracting the Butterfat
With a long-handled spoon, skim the top foam layer from the butter avoiding disturbing the butterfat.
Slowly pour the butterfat into a clean container. The water will sit at the bottom as you do this. Be sure not to let any water slip into the butterfat container.
You can take the three layers of butter and place them in the refrigerator. Allow them to solidify then pull it out of the container and scrape off the top layer. The liquid layer will remain in the container.
Though technically clarified butter does not need to be refrigerated because bacteria does not work away at pure oil, there could still be remaining protein that would cause it to go rancid more quickly.
“How to Make Clarified Butter.” Le Cordon Bleu. N.p., n.d. Web. 24 Sept. 2012. <www.chefs.edu/Student-Life/Culinary-Central/September-2011/How-To-Make-Clarified-Butter>.
“Learning, Food Resource [http://food.oregonstate.edu/], Oregon State University, Corvallis, OR.” Food Resource [http://food.oregonstate.edu/], Oregon State University, Corvallis, OR. N.p., n.d. Web. 24 Sept. 2012. <http://food.oregonstate.edu/learn/faq/faq_butter1.html>