Preheat oven to 350º F. Grease two 9-inch round cake pans with cooking spray and lightly dust with some flour or cocoa powder
In mixing bowl, I use my Kitchen Aid, add flour, sugar, cocoa, baking powder, baking soda, and salt. Stir until well combined.
Add milk, vegetable oil, eggs, and vanilla to flour mixture and mix together on medium speed until well mixed. Reduce the speed to low and add boiling water to the cake batter a little bit at a time. Once the water is all mixed in beat on high for about 1 minute.
Evenly distribute cake batter between the prepared cake pans.
Bake for 30-35 minutes, until a toothpick or cake tester inserted in the center comes out clean.
Remove from the oven and allow to cool for about 10 minutes, remove from the pan and cool completely.
**Don't worry if the cake falls in the center, it will still turn out just fine. I have this happen every once in a while, for instance when I forget to stick the cake in the oven and it sits on the counter for a while....not that I do that too much. (wink, wink)**
In a small sauce pan add the whipping cream and bring 1 cup to a boil, remove from heat and add in chocolate chips. Do not mix or stir them in, let the chocolate sit for 5 minutes. Stir until smooth. Let it cool to room temp, you do not want it warm or hot.
In a large bowl, beat 2 cups chilled cream with 1/4 cup sugar. Beat until stiff peaks form. Fold whipped cream into chocolate mixture.
Set in the refrigerator until ready to use to layer cakes.
Cut each round cake in half. Place one layer on a cake plate or the serving plate you will be using. Add 1/3 of the chocolate mousse, you don't need to be exact just eyeball it.
Allow the cake to chill in the refrigerator for 2-4 hours. Then frost the cake with the chocolate buttercream.
Set back in the refrigerator until ready to cut, serve and devour.
In a stand mixer cream together butter and cocoa powder until well-combined.
Add powder sugar and milk to cocoa mixture by adding 1 cup of sugar followed by about a tablespoon of milk. After each addition has been combined, turn mixer onto a high speed for about a minute. Repeat until all sugar and milk have been added.
Add vanilla extract and mix well.
Tip to get the right consistency of frosting you may need to add additional milk or powdered sugar. If frosting appears too dry, add more milk, a tablespoon at a time until it reaches the right consistency. If it appears to wet and does not hold its form, add more confectioner’s sugar, a tablespoon at a time until it reaches the right consistency.
Store the remaining cake in the refrigerator, if there are any leftovers.