Black Walnut Buttermilk Candy

1 cup sugar
1/8 teaspoon salt
1/2 teaspoon baking soda
1/2 cup buttermilk
1/2 teaspoon maple flavoring
1 cup coarse chopped black walnuts
3 tablespoons butter

Combine the sugar, salt, soda, and buttermilk in a heavy pan. Cook to 235�F on a candy thermometer, stirring constantly. You will need a fairly heavy deep narrow pan as this mixture foams as you cook it. Remove from the heat and stir in the maple flavoring, chopped walnuts and butter. Beat either by hand or with a mixer until thick and creamy. Drop by small teaspoonfuls onto waxed paper and let cool. Store in airtight container.