Double Chocolate Bombe

Directions

1. 1
   Process pecans in a food processor until ground; set aside.
2. 2
   Beat butter and shortening at medium speed with an electric mixer until creamy; gradually add sugar, beating well. Add vanilla, beating until blended. Add egg yolks, 1 at a time, beating until blended after each addition.
3. 3
   Combine flour, soda, and pecans; add to sugar mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at low speed until blended after each addition.
4. 4
   Beat egg whites until stiff peaks form; fold into batter. Pour into a well-greased and floured 15- x 10-inch jellyroll pan.
5. 5
   Bake at 350° for 20 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack 10 minutes; remove from pan, and cool on wire rack.
6. 6
   Line a 3-quart mixing bowl (8 1/2 inches across) with plastic wrap.
7. 7
   Cut cake lengthwise into 2-inch strips; line prepared bowl with cake strips, reserving remainder. Spread Chocolate Mousse over cake in bowl; cover and chill 1 hour.
8. 8
   Pour White Chocolate Mousse into bowl over chocolate layer; cover and chill 1 hour. Cover with remaining strips. Cover and chill at least 8 hours.
9. 9
   Invert bombe onto a cake plate, and spread with ganache. Garnish, if desired.