• Preheat the oven to 325°F (160°C). Prepare 9-inch or 22cm cake pans with non-stick baking spray and 9-inch (22 cm) parchment circles.
• Add flour, baking soda, baking powder, salt, and mini chocolate chips to a medium-sized bowl. Whisk well to mix. Set aside.
  
• In another medium bowl, add unsweetened chocolate, cocoa powder, and espresso powder (if using). Pour hot water over the mixture, stir to coat the cocoa with liquid, and let sit and bloom for at least 5 minutes. Stir into a paste and microwave for 15 seconds if the chocolate pieces still need to melt.
  
• Add the butter and sugars to a large bowl and beat together at high speed with a hand or stand mixer until the mixture is fluffy and lighter in color.
  
• Add eggs one at a time, scraping the bowl as needed.
  
• Add the chocolate mixture and continue mixing until incorporated.
  
• Scrape the bowl and alternate adding the dry mixture and the sour cream-and-buttermilk mixture, starting with a third of the dry mixture, then half of the wet mixture, alternating until all the flour has been added.
  
• Mix on low speed just until the ingredients are combined.
  
• Divide the batter between the two prepared round cake pans (850g per pan).
  
• Place both pans in the oven and bake at 325°F (160°C) for 33-35 minutes, or until, when lightly touched, the cakes bounce back. Test with a toothpick; you want a few moist crumbs, not liquid batter.
  

To make the Cherry Compote and cherry syrup:

• While the cakes are baking, prepare the cherry compote by first making a slurry of cornstarch and water in a small bowl. Set aside. Place the cherries, sugar, orange zest, and orange juice in a medium-sized saucepan.
  
• Stir on medium heat until the sugar has dissolved, then stir occasionally until the cherries have released their juices.
  
• Re-stir the cornstarch slurry, then slowly pour it into the cherry mixture while stirring. Stir until the mixture thickens.
  
• Pour into a bowl and chill in the refrigerator.
  
• To make a quick cherry syrup to brush on the cakes, combine the simple syrup, the liquid from the cherry compote and the Kirsh or cherry liqueur in a bowl and mix well.
• Remove the cakes from the oven and cool in the cake pans at room temperature. Leave the cake in the pans to cool until ready to use. Or once completely cool, wrap in plastic wrap to use later.
  

To make the mascarpone frosting and the chocolate ganache (do this right before assembling the cake):

• Add all the ingredients (mascarpone, powdered sugar, heavy cream and orange zest) to a mixing bowl, using a hand mixer or stand mixer, whip the ingredients on low speed until incorporated, then on high speed until firm peaks form.
  
• Make the ganache by adding all ingredients to a small bowl. Microwave for 1 minute, then stir. Microwave for another 15-30 seconds as needed to melt the chocolate. Stir until the ganache is thick and shiny.

To assemble the cake:

• Place one layer on a cake plate. Use a pastry brush and brush the cake with the syrup, you can also gently spoon some of the syrup on the cake until it is absorbed.
  
• Next, pour half the ganache on top of the layer and spread to the edge (or even over the edge in some places).
  
• Add the chilled cherry compote to the top until completely covered.
  
• Using a disposable decorating bag fitted with a 1M tip, pipe small swirls of mascarpone frosting onto the cherry compote.
  
• Add the second cake layer and repeat.
  
• For a fun look, add fresh cherries on top of the cake.
  
• If there is a little extra compote, chocolate ganache and/or mascarpone frosting, serve it on the side of each slice of cake.