1. Preheat oven to 350 degrees F or 170 degrees C.
2. Butter/grease or put down parchment paper on one square pan 8×8 inches.
3. Whisk the eggs and sugar until well combined.
4. Add in all the rest of the ingredients and gently whisk (or use a spatula) to stir it all together until combined.
5. Pour the batter into the pan and bake for about 35-40 minutes or until you insert a toothpick or knife in the center and it comes out clean.
6. OR
7. Scoop a small amount of batter into the cake pan, making a simple thin layer. If you prefer, measure out the batter to ensure even layers…I used about 1 cup of batter for each layer (I had two slices left over that were too crumbly so I made cake balls out of them instead).
8. Wrap a wet baking strip or wet towel around the pan to ensure easy removal.
9. Bake for about 10-15 minutes or until a cake tester comes out clean.
10. Let cool before turning over onto parchment paper.
11. Repeat until the batter is finished.
12. Place the layers in the freezer with parchment paper between each until chilled.

For the Mousse

1. Heat 2 cups of the cream and add 6 oz of milk chocolate chips to the saucepan.
2. Stir on low heat until well incorporated with no bits of chocolate.
3. Pour into a clean bowl, cover with wrap, and chill for at least 2 hours or overnight.
4. Beat the chilled mix with an electric beater till it thickens to a mousse consistency.
5. Do not over mix as it will curdle!
6. Chill until ready to use.
7. Repeat with 2 cups of the cream per 6 ounces of dark chocolate chips.
8. For the white chocolate chips, use only 1 1/2 cups cream, and whisk in the butter at the room temperature if the mousse is not holding up well.

For the Frosting

1. Add the espresso powder to the cocoa powder.
2. Bring 1 cup of heavy whipping cream to a boil in a small saucepan.
3. Slowly pour the cream over the cocoa mixture, whisking until the cocoa/espresso is completely dissolved.
4. Add the sugar, and when dissolved, add in the remaining ½ cup heavy whipping cream.
5. Chill in the fridge until cold, at least two hours or overnight.
6. Use an electric beater to beat the mixture until it thickens.
7. Add in all the mascarpone and beat on low until well-combined (mascarpone can curdle quickly so be gentle).

Assembly

1. Spread Chambord or liqueur of your choice over a layer of cake before spreading on the mousse. I put in about a tablespoon on each slice.
2. Spread the mousse evenly on top of the layer and top with another slice.
3. Repeat until finished.
4. Frost with the mascarpone espresso frosting.