In medium saucepan melt butter and chocolate over low heat. Remove and stir in sugar. Blend in eggs one at a time. Add vanilla. Stir in flour and nuts and mix well. Spread in greased 8" or 9" square or round pan. Bake at 375 degree oven for 25 minutes
Place brown sugar in sauce pan. Melt together. Cool a few minutes. Add eggs, flour, vanilla and nuts. Mix just until blended. Place in medium size baking pan. Bake for 25 minutes or until tan in color and toothpick comes out clean. Cut while warm.