Preheat oven 350F. In mixing bowl, cream butter and sugar. Beat in eggs and vanilla. Add flour and salt; mix well. Fold in walnuts. Spread half of the batter into a greased 9 x 13 x 2 inch baking pan. Add chocolate to the remaining better; mix well. Carefully spread over batter in pan. Bake for 30-35 minutes or until cake tests done. Cool completely.
Mmix flour and milk in a saucepan. Cook and stir over medium heat until a thick paste forms, about 10 minutes. Cool completely. In a mixing bowl, cream butter and confectioners sugar. Add vanilla and mix well. Gradually add the medium mixture; beat for 5 minutes. Frost cake.
Cajun Country -- New Iberia, Louisiana