1. Drain pitted cherries (if using canned). Place them in a bowl, add golden rum and 1 tablespoon sugar, let stand at room temperature for an hour. Then drain and keep the syrup and cherries separately for later use.
2. Preheat oven to 350F (180C). Line bottom of a 9-inch springform pan with parchment paper. Brush the sides with oil (it will make it easier to remove the cake).
3. Separate egg yolks from egg whites. Using an electric mixer, beat egg whites and gradually add half of the sugar until stiff peaks form. Set aside.
4. In a large bowl, beat egg yolks with the rest of the sugar until pale yellow.
5. In a separate bowl, mix together flour, baking powder and cocoa powder.
6. Add half of the egg whites mixture to the egg yolks mixture, gently stir. Start to gradually sift flour over top and fold it in, small portions at a time (be patient with this step). Then add the rest of the egg whites mixture and fold by gently scooping from bottom up to the top, just until incorporated and smooth.
7. Transfer mixture to the prepared pan.
8. Bake in the preheated oven for about 1 hour, until a toothpick inserted in the center comes out clean.
9. Let cool completely. Once the cake is cool loosen sides with a spatula and remove from pan.
10. For the filling, beat together softened butter and sweetened condensed milk (scraping down the bowl). Gradually mix in the softened cream cheese, small portion at a time.
11. In a separate bowl, beat cold whipping cream until stiff peaks form. Add to the rest of the cream cheese mixture and stir until well blended. You can reserve few tablespoons to decorate cake.
12. Cut the ¾ inch top off the cake (we will need it later to cover the cake).
13. With your fingers, make a large well in the cake, leaving about ¾ inch wide walls. Coarsely crumble the cake part that you removed.
14. Finish the filling. In a large bowl, mix together cake crumbles (leave some to decorate sides of the cake), prepared filling mixture and drained cherries.
15. Stir water into the reserved cherry rum liquid (if using canned cherries, you can use the syrup instead of water). Generously brush the bottom, sides of the cake, and the bottom part of the cake top with this liquid.
16. Fill the cake well with the filling and top with the reserved cake top. Refrigerate.
17. Prepare the ganache. In a saucepan, bring heavy cream to a simmer, stirring occasionally. Add chocolate chips, make sure all the chips are covered with cream. Place a lid on top and let stand for 5-7 minutes, then stir with a whisk until smooth. Let stand for 10-15 minutes to thicken.
18. Pour half the ganache over top, then slowly but steadily pour around edges, allowing to drip down the sides. I used a spoon to get an even coverage, and a piece of paper towel to clean the plate.
19. Decorate sides of the cake with the reserved crushed crumbs. I put some crumbs on my palm then gently pressed them against sides of the cake. Decorate top with cherries and reserved cream/filling mixture.