Still my favorite candy.

2 cups brown sugar
2 teaspoons vinegar
1 cup water
1 cup butter
1/2 teaspoon vanilla

-Put all of the above ingredients in a saucepan, and bring to the boiling point. Let boil without stirring until
mixture becomes brittle when tried in cold water (or to the hard crack stage on a candy thermometer).
-Pour into a buttered pan, which is covered with roughly chopped walnuts, no more than half-an-inch thick.
-When cold, break with knife into pieces.

-Sprinkle chocolate chips over the top while candy is still hot if so desired.

Source: Grandma