Melt the baking bar in a small pan over low heat, stirring constantly. Set aside.
In a small bowl, stir the flour, baking soda and ¼ teaspoon salt.
In a separate small bowl, beat the butter with an electric mixer at medium speed for 30 seconds. Add 1 cup sugar and beat until well combined. Beat in the melted baking bar, egg, buttermilk, and vanilla. Add the flour mixture; beat until well mixed. Cover, chill dough at least one hour, or until easy to handle.
Preheat the oven to 375 degrees F.
Shape the dough into 1 inch balls; roll in additional sugar. Place 2-inches apart on an ungreased cookie sheet. Bake for 10 minutes, or until bottoms are light brown. Remove and cool on wire rack.
Meanwhile, in saucepan, cook and stir chocolate chips and shortening over low heat until melted. Drizzle over cookies and sprinkle with crushed candy.
Notes
No buttermilk in your fridge? You may substitute milk plus ¾ teaspoon of lemon juice to get the same result.
Chocolate chips and shortening can just as easily be melted in a pyrex dish or measuring cup in the microwave. Heat a little at a time, stirring every 30 seconds, until the mixture is melted and smooth.