I am not sure where my mom got this recipe; but it is divine. It is very smooth. My family loves it as well as my extended family. I frequently give it as gifts to friends too, as it is often requested!
Butter the bottom and sides of a very large mixing bowl, a 2 quart saucepan, and an 8 x 14 inch pan. Combine chocolate, marshmallows and nuts in the large mixing bowl, and set aside.
Combine butter, sugar and milk in sauce pan. Cook over medium heat (stirring constantly but gently). Do not scrape sides of pan above the candy line. Cook to the softball stage (a small amount of candy will form a soft ball and hold together when worked with your hands under ice water).
Pour candy into mixing bowl with chocolate, etc. Beat vigorously until candy loses gloss and begins to set up. Pour and spread into a buttered 8 x 14 inch pan. Refrigerate until cool. Cut into squares. Store in the refrigerator.