1. Place a wire rack at mid-level in the oven and preheat to 350F/180C. Grease and line two 9 in/23 cm circular cake pans with butter and parchment paper; keep aside until ready to use.

2. Place the chocolate and cocoa in a medium-sized mixing bowl. Pour the boiling water into the bowl and whisk until all the chocolate has melted. Add 1/2 cup/100 g sugar to the melted chocolate mixture and stir until combined. Cool to room temperature.

3. In a medium mixing bowl, dry whisk the flour, baking soda, and salt. Whisk the buttermilk, vanilla, and kirsch in a small bowl.

4. Add the eggs and yolks to the bowl of a stand mixer. Using the whisk attachment, whisk on medium-low speed until combined for around 10 seconds. Pour in the remaining sugar and increase the speed to high. Whisk the eggs until light and fluffy but pale yellow, about 3 minutes. Remove the whisk and replace it with the paddle attachment.

5. Add the cooled chocolate mixture into the bowl and mix over medium-low speed. Scrape the sides of the bowl with a silicone spatula. Then add the butter, one tsp at a time, and mix for 10 seconds after each addition.

6. Add the flour mixture in 3 additions, alternating with the buttermilk mix in the last two. Mix over medium-low speed until completely combined and no visible flecks of flour can be seen. Divide the batter equally between the two prepared pans and bake them in the preheated oven for 25 to 30 minutes, rotating them halfway through the baking process. The cakes are done when a skewer comes out clean from the center after insertion, and the tops are firm to touch.

7. Allow the cakes to cool in the pan for 10 minutes. Remove the cakes from the pan by running a knife along the edges of the cake. Transfer to a wire rack and cool completely for at least two hours. Wrap the cakes individually in parchment paper and then aluminum foil. Freeze for at least 4 hours before assembling.

To Assemble the Cake:

1. Leave the ice cream outside to soften for at least 10 minutes. It should be soft enough to manipulate but not runny.

2. Line a 9 in/23 cm springform cake pan on the bottom and sides with parchment paper or cellulose acetate. Unwrap one of the frozen cakes and place it at the bottom of the springform pan. Layer the surface with about 2 cups of softened ice cream. Quickly place the second cake over the ice cream and repeat the layer of ice cream. Smoothen the layers of ice cream using an offset spatula. Cover the cake with aluminum foil and freeze for at least 4 hours before serving. Store in the freezer.

3. Pop the springform mechanism to release the cake and peel the parchment paper off. Decorate the cake with fresh cherries and semisweet dark chocolate shavings. The cones are optional.