Melt at low heat or over double boiler (or in microwave):
  1/2 cup butter
  2 one oz. squares of unsweetened chocolate

Remove from heat.

Add:
  1 cup sugar
  Blend in 2 eggs, one at a time
  Add 1 tsp. vanilla
  Stir in 3/4 cup sifted flour
  Add 1/2 cup chopped nuts

Mix it all well.

Spread in 8X8X2 inch pan, well greased.

Bake at 350 degrees for 30 minutes.  Be careful not to overbake.

Cool and sprinkle with powdered sugar.