This is Grandma's recipe as I copied it onto a recipe card when I was a girl:
1 lb walnuts
1 1/2 cup sugar
1/2 cup sour cream
1 1/2 T vanilla
Mix sugar and sour cream. Bring to a boil and boil 5 minutes. Remove from heat. Stir in vanilla. Add nuts and stir. Remove from pan. Put on waxed paper to dry. Separate; dry overnight.
I found that I had to keep stirring the mixture on the stove so it wouldn't burn on the bottom. You have to watch the clock carefully to make sure it is cooked long enough. A similar recipe here contains brown sugar in place of some of the sugar and instructs the cook to boil to 236 degrees using a candy thermometer. Other variations I saw listed the 2 cups of sugar along with the sour cream and 4 cups of walnuts. Enjoy!