Place parchment paper onto 2 baking sheets; set aside.
Place chocolate and butter into bowl; set aside.
Pour whipping cream into 1-quart saucepan; cook over medium-high heat 4-5 minutes or until cream comes to a boil. Pour hot whipping cream over chocolate mixture in bowl; let stand 2 minutes. Stir mixture with whisk until smooth. Pour into 8- or 9-inch square pan. Refrigerate at least 1 hour until firm enough to shape.
Sprinkle powdered sugar over clean hands; shape level tablespoons of chocolate mixture into balls. Place onto prepared baking sheets.
Place decorator sprinkles or sugars into bowls; set aside. Roll each truffle in desired coating. Place truffles in container with tight-fitting lid; refrigerate about 1 hour until firm. Store refrigerated.
*Substitute 10- to 12-ounce bag bittersweet or semi-sweet chocolate chips for chopped chocolate.
If mixture is too soft to roll into balls, refrigerate 10 to 15 minutes and try again.