1 cup brown sugar, firmly packed
1/2 cup granulated sugar
1/2 cup sour cream
2 1/2 cups walnuts, halved
1 teaspoon vanilla extract
Combine the sugars with the sour cream. Simmer, stirring, 2 to 3 minutes until the sugars are dissolved. Boil gently until it reaches a soft-ball stage or until it is about 235 degrees F on a candy thermometer. Remove from the heat. Add in the nuts and vanilla extract. Stir until the mixture starts to crystallize. Separate into 1 inch clusters, spread on wax paper to cool.
NOTE: Coarsely chopped, these can be used in frosting for a layer cake or as a topping for pudding or ice cream.