Preheat oven to 350o (if using glass pan 325o) Grease a 9/13 baking pan and set aside. Melt butter and chocolate in double boiler, cool slightly and add vanilla and set aside.
Beat eggs and sugar until pale in color and mix in chocolate mixture.
Whisk flour baking powder and salt together and add to chocolate mixture. Pour into pan and bake for 25 to 30 minutes. Do not over bake. Cool completely.
These do not need icing, but feel free to ice them if you wish....I do!! Melt 1&1/2 ounces of unsweetened bakers chocolate with 2 tablespoons of butter add a tsp of vanilla. Beat the mixture with a cup of icing sugar and add a few tsps of cream until you get a good spreading consistency....Enjoy