Preheat oven 350~. Grease and flour a 10 1/4x 15" baking pan. For the cake, melt chocolate and butter together over hot water. Set aside to cool. Place sugar, eggs, and vanilla in the bowl of a mixer and beat at med speed for 12 minutes. The eggs should be very pale and should form wide ribbons when the beaters are raised. While eggs are beating, sift together flour, pecans, salt, and soda. Alternately add buttermilk and the chocolate mixture to dry ingredients, then carefully fold in the beaten eggs until everything is just mixed. Pour batter into pan and bake for around 30 minutes or until cake tester comes out clean. Cool on cake rack. When completely cold, cut in half across the width and turn out the 2 halves. Place 1 layer on your cake platter. Set the other aside. To make topping, melt the chocolate over warm water. Let cool somewhat then, using an electric hand mixer, slowly add the cream. Beat continuously until mixture is as thick as whipped cream. Flavor with vanilla. Spread some of the filling on the bottom layer of the cake. Sprinkle on some toasted coconut and half the chopped pecans. Top with remaining cake layer (trim top to flatten it if necessary). Coat cake with chocolate cream mixture. Arrange 1 1/2" wide border of toasted coconut around the top edge. Place the whole pecans in a row around the inside coconut border. Leave the center of the cake plain. Press the remaining toasted coconut and chopped pecans into the sides of the cake. Place cake in the refrigerator to chill until served. ----