Bottom Layer (Chocolate Cake):

1. Preheat your oven to 350 degrees.
2. Line a 9 inch cake pan with a parchment paper circle and spray the cake pan edges with non-stick cooking spray.
3. Measure 1 Cup of sugar, 1 1/4 Cup flour, 1/2 Cup cocoa, 1/2 tsp baking powder, 1/2 tsp baking soda, and 1/2 tsp salt in a large mixing bowl.
4. Whisk to mix.
5. Add the eggs, 1/2 Cup milk, 1/4 Cup olive oil, and 1 tsp vanilla.
6. Beat until the batter is thick and well mixed.
7. Pour the 1/2 cup of boiling water (boiling, not just hot) into the batter while your beaters are running in a slow steady stream.
8. Beat the batter until the water is mixed in and the batter is very thin.
9. Pour the batter into the cake pan.
10. Bake at 350 degrees for 25-27 minutes.
11. Cool 20 minutes before turning out onto a wire rack.
12. Peel the parchment off the back and cool completely.
13. Level the top of the cake with a sharp serrated knife and eat the top you cut off.
14. Place the leveled cake in the bottom of a 9 inch springform pan.

Second Layer (Chocolate Mousse):

1. Carefully melt 3/4 Cup semi-sweet chocolate chips and 4 oz cream cheese together in the microwave. (Mine took about 30 seconds to melt).
2. Whisk together and make sure no chocolate lumps remain.
3. Allow to cool while you do the next few steps.
4. In a small bowl mix 1 Tbs. cold water with 1 tsp unflavored gelatin to soften the gelatin.
5. Then whisk 2 Tbs. boiling water into the softened gelatin to dissolve it.
6. Measure 1 Cup heavy cream into a deep bowl or 4 cup measuring cup.
7. Add 1/4 Cup powdered sugar and dissolved gelatin to the heavy cream.
8. Beat at a high speed until stiff peaks form.
9. Fold the chocolate cream cheese mixture into the whipped cream.
10. Continue folding until it's completely mixed in.
11. Spread the chocolate mousse evenly over the chocolate cake layer.
12. Put in the fridge while you prepare the white chocolate mousse layer.

Third Layer (White Chocolate Mousse):

1. In a small bowl soften 1 tsp unflavored gelatin in 1 Tbs. cold water.
2. Bring 1/2 Cup of heavy cream to a boil.
3. Whisk the softened gelatin into the boiling cream and whisk until dissolved.
4. Pour the boiling cream over 1 Cup white chocolate chips.
5. Stir until the chips are melted and completely smooth.
6. Measure 1 Cup of heavy cream into a deep bowl or measuring cup.
7. Beat until stiff peaks form.
8. Fold the melted white chocolate into the whipped cream.
9. Continue to fold until it's completed incorporated.
10. Spread the white chocolate mousse over the chocolate mousse layer.
11. Place in the fridge and chill for at least an hour before doing the ganache layer.

Fourth Layer (Chocolate Ganache):

1. Bring 1 1/2 Cup of heavy cream to a boil.
2. In a deep bowl or measuring cup pour the boiling cream over 3 1/4 Cups or an 18 oz bag of semi-sweet chocolate chips.
3. Whisk until all the chocolate chips are melted and the mixture is completely smooth.
4. Allow to cool until the ganache is still pourable but not a hot liquid.
5. Loosen the mousse cake by running a sharp knife around the edges.
6. Remove the springform pan rim.
7. Once the ganache has cooled to a pourable but not hot state pour some over the top mousse cake, spreading it carefully allowing it to run down the edges and smoothing it around the edges as well.
8. You will use 2/3rds of the ganache to coat the cake.
9. Press mini semi-sweet chocolate chips to the ganache coated sides of the cake. Yes, this is a bit messy.
10. Place the cake back in the fridge and let it chill while the remaining ganache cools and sets up to a pipeable consistency.
11. If you're wanting to transfer the mousse cake to a cake plate this is time.
12. Carefully slide a spatula under the mousse cake and loosen the entire cake from the springform pan bottom.
13. Carefully slid onto a cake plate.
14. Scoop the ganache into a frosting bag fitted with a large decorative tip of your choice. I usually use a large star tip.
15. Pipe the ganache around the top and bottom edges of the mousse cake.
16. Melt the white chocolate and drizzle or pipe over the middle of the cake.
17. Place the cake back in the fridge to set the ganache and chill all the way through for at least 4 hours.
18. Slice and serve when ready.