Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   4      ounces        unsweetened chocolate
     1/2  cup           butter -- room temperature
   1 1/4  cups          sugar
     1/4  teaspoon      salt
   2      teaspoons     vanilla
   4      large         eggs -- room temperature
     2/3  cup           sifted all-purpose flour
   1 1/4  cups          walnut pieces

Preparation:

Preheat oven to 325*F. Grease a 9x9-in.metal baking pan lightly or line with parchment paper. Melt chocolate in double boiler, over simmering but not boiling water. Cool to room temperature. Cream butter until fluffy. Add sugar in thirds continuing to beat the mixture until light and fluffy. Add the eggs, 1 at a time beating each in well. Mix in melted chocolate. Fold in flour by hand. Do not overmix. Fold in the nuts if using them. Pour batter into prepared pan. Bake for 22 to 25 minutes. If you are using a glass baking dish bake 17 to 20 minutes. Until top is dry and a toothpick in center comes out clean. Cool completely in pan before cutting.