Heath bar brunch cake

1/2   c            butter
   1 1/2   c            Light brown sugar, packed
     1/2   c            Sugar
   2       c            flour, sifted
     1/4   ts           Salt
   1       c            buttermilk
   1       t            Baking soda
     1/8   ts           Salt
   1                    Egg, slightly beaten
   1       t            vanilla
   2                    1-1/8oz Heath Bars, finely
                        - crushed  (chilled)
     3/4   c            Pecans, finely chopped
   6                    1-1/8oz Heath Bars, finely
                        - crushed (chilled)

  Preheat oven to 350~F. Cream butter and gradually add
  the light brown sugar and sugar. Blend in flour and
  1/4 ts salt; mix well. Reserve 1 cup of this mixture
  for topping. Combine buttermilk, baking soda, 1/8 ts
  salt, egg and vanilla. Stir into remaining
  butter-sugar mix. Fold in 2 finely chopped Heath bars.
  Turn into a buttered 13 x 9 pan and sprinkle with the
  1 cup reserved topping, then with the pecans. Top with
  additional 6 crushed Heath bars. Bake for 35 - 40
  minutes. Serve with cocoa-flavored whipped cream or
  with coffee ice cream.