LINE 8-inch-square baking pan with foil.
COMBINE butter, evaporated milk, sugar and salt in medium, heavy-duty saucepan. Bring to a full rolling boil, stirring constantly, over medium heat. Boil, stirring constantly, for 4 1/2 to 5 minutes. Remove from heat.
STIR in marshmallows, morsels, nuts and maple flavoring. Stir vigorously for 1 minute or until marshmallows are melted. Pour into prepared baking pan. On top of fudge, place nut halves in rows spacing about 1/2 inch apart. Press into fudge; refrigerate until firm. Cut into 48 squares with 1 nut half per square.