For Chocolate Genoise Cake: Preheat oven to 350° F. Line a 9x3-inch springform pan with parchment paper (cut a circle to fit if necessary). Sift flour and cocoa powder together into a small bowl and set aside.
In a stand mixer fitted with a paddle attachment, beat eggs and sugar on high speed for about 10 minutes until the batter is pale yellow in color and ribbons when you drop a spoonful of it back into the mixture. Reduce to medium speed and continue mixing for another 10 minutes. Remove the mixer bowl and gently fold in the sifted flour and cocoa powder. Bake for about 30 to 40 minutes (rotating pans halfway through) until a toothpick inserted into the center of the cake comes out clean. Place on a rack and allow to cool completely.
For Tart Cherry Compote: Drain cherries, reserving juice (you should have about a ½ cup of juice, but top off with some water if there's not enough). Combine cherry juice, sugar, and cornstarch in a medium saucepan and cook on medium heat, whisking constantly, until thickened. Gently fold in cherries, and then set aside to cool (if compote is runny, keep cooking until it reaches the consistency of pie filling).
For Kirsch Simple Syrup: Mix sugar and water together in a small saucepan and boil for one minute. Add kirsch to taste. Set syrup aside and allow it to cool.
For Kirsch Cream: In a small saucepan, mix sugar and gelatin together, add kirsch, and then heat until it all gels. Place mixture inside a large bowl and allow it to cool to about 85⁰ to 95⁰ F. Gently fold in about a quarter of the whipped cream, and then fold in the rest.
To Assemble: Carefully take the cake out of the pan by running a small knife along the edge to loosen and by releasing the spring, and then set it on a cutting board. Trim the top and bottom of the cake to take off any crust, and slice it evenly into three layers. (Clean and dry springform pan.)
Place one of the cake layers back into the clean springform pan, and then brush it (soaking to your liking) with kirsch simple syrup. With an offset spatula, evenly spread the cherry compote on top and then add about a third of the cream, leveling it off with a spatula. Add another cake layer, more kirsch syrup, and another third of the cream. Place the final cake layer on top and gently press down into the pan to even out all the layers, and then brush with the remaining kirsch syrup. Add the rest of the cream to fill the pan, and then level off with a spatula. Refrigerate for at least an hour, overnight if possible.
Carefully remove the cake from the pan, again, by running a knife along the edge and releasing the spring. Transfer the cake to a plate. Whip the heavy cream, making sure not to over beat, and frost the cake (To prevent any crumbs from mixing in to the beautiful white cream, I like to add a "crumb layer" first by spreading a thin layer of whipped cream on the top and sides of the cake and refrigerating for about 15 minutes). Decorate with chocolate curls, piped whipped cream swirls, and cherries.