Trace three 9-inch cake pans onto sheets of wax paper. Cut out wax paper circles. Grease the cake pans well with shortening. Place wax paper in bottom of pans. Grease well again over the wax paper. Flour pans well.
Melt chocolate morsels in the microwave on HIGH for 30-second intervals until melted (about 1 1/2 minutes). Stir until smooth.
Beat softened butter and brown sugar at medium speed for about 5 minutes or until well blended. Add eggs, one at a time, beating just until blended after each addition. Add melted chocolate, beating until blended.
Sift together flour, baking soda & salt. Gradually add to chocolate mixture alternately with sour cream, beginning and ending with flour mixture. Add hot water. Beat at low speed just until blended. Stir in vanilla. Pour batter evenly into prepared pans.
Bake at 350°f for 30 minutes or until wooden pick comes out clean. Cool in pans on wire rack 10 minutes; remove from pans and let cool completely on wire racks. Remove wax paper. Spread Peppermint Filling evenly between cake layers. Spread Chocolate Ganache evenly on top and sides of cake. (garnish with chopped peppermint candy, if desired).
For the Peppermint Filling.
Beat butter at medium speed until creamy; gradually add powdered sugar alternately with milk, beginning and ending with powdered sugar. Beat after each addition at low speed. Stir in peppermint extract.
For the Ganache.
Microwave chocolate morsels and whipping cream in at 2 quart bowl at MEDIUM power FOR 2 1/2 to 3 minutes or until chocolate begins to melt. Whisk until chocolate melts and mixture is smooth. Whisk in butter and let stand 20 minutes.
Beat at medium speed 3 to 4 minutes or until soft peaks form.