Preparation / Directions:
Preheat oven at 375.
Generously grease the bottom only of a 13 x 9 inch pan.
Melt 1/2 cup of chocolate pieces over hot water; set aside.
In small saucepan, melt butter, stir in graham cracker crumbs. Let cool while preparing cake batter.
In large mixer bowl, combine flour, sugar, salt, soda, vanilla, shortening, buttermilk, eggs and melted chocolate. Blend at low speed, bet 3 minutes at medium speed, scraping bowl occasionally.
Pour batter in prepared pan, spreading to edges.
Add walnuts and remaining chocolate pieces to cooled crumb mixture. Sprinkle over batter.
Bake at 375 for 35 to 40 minutes until top springs back when touched lightly in center.