Mamie Eisenhower's Favorite Fudge

This is also known as White House Fudge, Mamie's Fudge, Mrs. Eisenhower's Fudge, Million Dollar Fudge and Mamie's Million Dollar Fudge.

1 2/3 cups evaporated milk
4 cups granulated sugar
2 tablespoons butter
2 cups semisweet chocolate pieces
3 (4 ounce) bars sweet cooking chocolate
1 pint Marshmallow Cr?me
2 cups chopped pecans
1 teaspoon vanilla extract

Combine milk, butter, sugar and salt. Bring to a vigorous boil, stirring often; then reduce heat and simmer 6 minutes.

Meanwhile, place remaining ingredients (except pecans) in a large bowl. Gradually pour boiling syrup over the chocolate-marshmallow mixture and beat until chocolate is melted. Stir in nuts. Pour into buttered pans and store in a cool place several hours to harden before cutting in squares.