Preheat oven to 350°. Line the bottom of a 10-inch springform pan with parchment paper. Lightly grease and flour paper and sides of pan.
Stir together first 9 ingredients until well blended; fold in 1 cup chocolate morsels. Pour batter into prepared pan, and spread evenly over bottom.
Bake on middle rack at 350° for 20 to 25 minutes. Remove from oven, and sprinkle top evenly with marshmallows, pecans, and 1/2 cup chocolate mini morsels. Place on a wire rack, and let cool. Pour hot Chocolate Pudding over marshmallow mixture; cover and chill 8 hours or overnight.
Heat cream in a saucepan; bring to a simmer. Remove pan from heat, and add chocolate pieces, stirring until chocolate melts. Let ganache stand 1 hour, stirring occasionally, until spreading consistency. Remove sides from springform pan; pour and spread chocolate mixture evenly on top and sides of cake.
TIP: When putting the chocolate ganache on this dessert, you may need to pour on a layer, let it set; then pour on an additional layer, and chill. Don't worry if you have ganache left over--simply freeze it for another use.