For the Chocolate Sponge Cake:

1. Preheat the oven to 350°F.
2. Generously grease the bottoms and sides of 3 8-inch cake pans with butter or nonstick cooking spray. Line the bottom of each pan with an 8-inch parchment paper circle. Grease the parchment paper.
3. Place the eggs and granulated sugar in the bowl of a stand mixer fitted with the whisk attachment. On high speed, vigorously whisk the eggs and sugar together until the mixture is very fluffy and pale in color, about 10-15 minutes. The mixture will nearly quadruple in volume, and should flow off the lifted whisk in a steady stream in thick ribbons.
4. Whisk together the cake flour, cocoa powder, baking powder, and salt in a small bowl and set aside.
5. Carefully pour the eggs and sugar into a large bowl. In 3 separate additions, sift the dry ingredient mix on top of the egg mixture. Using a flexible spatula or bowl scraper, very carefully and slowly fold the dry mix into the eggs, trying not to deflate the volume. Continue folding until the ingredients are fully combined and a dark brown batter forms.
6. Using your spatula, distribute the batter evenly between the three greased cake pans.
7. Transfer the cake pans to the oven and bake without disturbing them for 15-20 minutes, or until the cakes have risen and the top springs back lightly when you very gently tap it with a finger.
8. Immediately remove the pans from the oven and place onto cooling racks to rest for 5-10 minutes. Quickly invert each pan and peel off the parchment paper from the base of each cake. Turn the cakes right side up on the cooling racks.
9. Allow the cakes to cool completely before decorating, for at least 4 hours or up to one day.

For the Cherry Filling and Soak:

1. While the cakes are cooling, prepare the cherry filling.
2. Whisk together the sugar, cornstarch, and 1/4 cup cherry liqueur in a medium saucepot. Place over medium heat on the stovetop. Whisking occasionally, heat until the sugar has dissolved and the liquid starts to bubble.
3. Stir in the cherries and continue stirring occasionally over medium heat. Cook until the liquid released by the cherries reduces and thickens significantly, about 10-15 minutes – the liquid should have a thickness similar to a thick pie filling.
4. Remove from the heat. Pour the mixture through a fine mesh strainer into a heatproof bowl, stirring without crushing the cherries, to strain out about 1/4 cup of liquid.
5. Whisk the remaining two tablespoons of liqueur into the liquid and set aside to cool completely at room temperature. This will be used to soak the top of each cake round when assembling.
6. Transfer the cherries and remaining liquid to a separate bowl and set aside to cool completely at room temperature. The liquid will thicken slightly.

For the Whipped Cream:

1. When ready to assemble, pour the whipping cream into the chilled bowl of a stand mixer fitted with a chilled whisk attachment. Whisk at medium speed until slightly fluffy, about 1-2 minutes.
2. Add the powdered sugar and vanilla extract. Continue whisking at medium speed, gradually increasing the speed to high as the mixture thickens, until stiff peaks form, another 3-5 minutes.
3. Immediately transfer the whipped cream to the refrigerator. Store in the refrigerator for no longer than 30 minutes prior to assembly.

To Assemble:

1. If necessary, level the top of each cake, reserving any cake crumbs for another use.
2. Set out the whipped cream, cherries, and cherry soak. Transfer about 1/2 cup of whipped cream into a piping bag fitted with a 1/2-inch round tip.
3. Working quickly, place one cake layer on a flat surface such as a cake stand, serving plate, or turntable. Using a pastry brush, evenly brush about half of the cherry juice soak on top.
4. Top the cake with approximately 1 cup of whipped cream from what remains in the bowl and spread evenly in a flat layer. Pipe a 1/2-inch dam of whipped cream around the perimeter of the cake.
5. Spread about half of the cherries inside the dam.
6. Repeat with the second cake layer.
7. Place the final cake layer on top. With the remaining whipped cream, frost the top and outside of the cake. If desired, decorate the top of the cake with more whipped cream, or any additional decorations like fresh cherries, sprinkles, ganache, or shaved chocolate.
8. Immediately transfer the cake to the refrigerator and let chill for at least 1-2 hours before serving. Due to the delicacy of the whipped cream, this cake will keep for up to 2 days max in the refrigerator.