Combine the sugars and the sour cream in a saucepan.
Cook over low heat, stirring constantly, until the sugars are dissolved.
Then continue cooking over low heat to 246°F., or until a little of the mixture dropped in cold water forms a ball a little firmer than a soft ball.
Remove, from the heat, and add the vanilla and nuts.
Stir until a light sugar-coating begins to form on the nuts.
Turn onto waxed paper or a tray, and separate the sugar-coated nuts.