Grease or line a 9x9 baking dish (line with foil or parchment paper - or grease well with butter or food release)
Heat butter in a saucepan over medium heat until nearly completely melted.Add cream, salt, and sugar, stirring until sugar melts, continue to heat, stirring occasionally until candy begins to boil.
Remove pan from heat, add candy melts, marshmallow cream, and peppermint extract. Stir vigorously until smooth -return to heat if necessary (if too stiff to mix)
Pour into baking dish Let sit at room temperature for 3-4 hours or in the refrigerator for 1-2-until firm
Decorate with sprinkles or shamrocks made with icing -if you choose , Cut and Serve