In a small pan, melt the chocolate with the water. Stir in 2/3 cup sugar.
Heat to boiling, stirring constantly.
Remove from heat. Stir in butter or margarine and 1 1/2 teaspoons vanilla. Set aside.
Blend together flour, 3/4 cup sugar, baking powder, salt, shortening, milk, and 1/2 teaspoon vanilla with an electric mixer on low speed to mix. Beat on medium speed for 2 minutes.
Mix in the egg. Beat 2 minutes more.
Pour batter into the pastry lined pan. Stir chocolate mixture, and pour over batter.
Sprinkle with the nuts.
Bake in a 350 degrees F (175 degrees C) for 55 to 60 minutes.