In large mixing bowl, cream remaining 1/2 cup butter and sugar for 3-4 minutes. Adds eggs individually, mixing well after each egg is added.
Add 1/3 of the flour and soda, 1/2 of the buttermilk, 1/3 of the flour and soda, remaining buttermilk, and remaining flour and soda. Mix well after each addition.
Add cooled candy bars and butter. Stir in pecans and vanilla.