Chocolate Mousse Cake

My coworkers have made it abundantly clear that they love chocolate. I've made a number of different cakes for them and the chocolate ones always receive rave reviews (after a bit of silent savoring). So for our December birthdays I thought I would pull out all the stops: chocolate mousse cake. Chocolate cake filled with chocolate mousse and topped with straight-up chocolate. Talk about a chocolate-lover's dream...

Chocolate Mousse Cake
Ingredients
Mousse
1 package gelatin
3T cold water
1/4 cup boiling water
1 cup sugar
1/2 cup cocoa powder
3 cup heavy whipping cream
Cake
2 cup flour
2 cup sugar
3/4 cup cocoa powder
1.5 tsp baking powder
1.5 tsp baking soda
3/4 tsp salt
1 cup milk
1 cup brewed coffee
3/4 cup vegetable shortening
2 eggs
1 block of bittersweet chocolate

Instructions
Mousse
1. Combine gelatin and cold water in a small bowl. Let it stand for about 2 minutes, then pour in boiling water. Stir mixture until gelatin dissolves. Set gelatin mixture aside.
2. In another small bowl, combine sugar and cocoa powder.
3. Beat cream in a standing mixer until it becomes foamy. Gradually add sugar-cocoa mixture. Beat until the soft peak stage. Thoroughly beat in gelatin mixture, but do not overbeat the cream. Cover and chill the mousse for at least 4 hours.

Cake
1. Preheat oven to 350 degrees. Grease two 9" round cake pans and line bottom with a round of parchment. In a large bowl, combine flour, sugar, cocoa powder, baking powder, baking soda, and salt. Add milk, brewed coffee, vegetable oil, and eggs, beating mixture until smooth.
2. Split mixture between two prepared cake pans. Bake for 20-25 minutes until a wooden toothpick comes out clean. Let cool for 10 minutes, then remove from pans and let cool completely, about 1 hour.

Assemble Cake
1. With a serrated knife, cut off the top of one cake so it is level. Place this layer, cut side up, on a serving plate. Spread half of mousse over this layer (perhaps less, depending on how moussey you want it). Carefully place remaining cake layer on top of the first layer. Spread the remaining mousse around the top.
2. Microwave block of chocolate in 5 second bursts at half power until soft but not melted, about 15 seconds. Using a vegetable peeler along the edge of the block, make chocolate curls and shavings.
3. Top cake with chocolate curls. Refrigerate cake until serving.