Preheat the oven to 350°F. Line the bottom of each cake pan with parchment paper.
Sift the flour, baking powder, baking soda, and salt into a medium bowl and whisk.
Put the cocoa powder in a medium heatproof bowl. Bring 3 cups water to a boil, then carefully measure exactly 2 cups and pour over the cocoa powder and whisk until completely smooth. Set aside to cool slightly.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar on medium speed until light and fluffy, about 8 minutes.
Add the eggs, two at a time, beating until each addition is incorporated before adding the next. Scrape down the sides of the bowl with a spatula when necessary.
Add the flour mixture in four parts, alternating with the warm cocoa mixture in three parts, beating just until each addition is incorporated before adding the next; do not overmix.
Pour the batter into the prepared pan or pans. Bake until a toothpick inserted in the center comes out clean, about 45 minutes
Transfer to a wire rack and let cool completely in the pan(s). Cover tightly with plastic wrap and refrigerate overnight. Loosen the edges with a straight spatula, invert the pan(s) to remove the cake, and peel off the parchment
For the ganache frosting ,heat the fresh cream till it slightly sizzles , pour it over the chocolate and butter.
Make sure there are no bits of chocolate, if found microwave the whole bowl for another 20 seconds and give it a good mix
Allow it to set for 2 hours in the fridge or overnight outside
Remove the chilled cake , place on a turn table and using a sharp knife trim the top if required, repeat for all layers . Place a cake board on the turn table , apply a little of frosting , spread evenly and start layering the trimmed sponges , alternating with ganache.
once the cake is layered, start covering the sides and top of the cake . Finish with a bench scraper
Top with desired frosting and chocolates
Chill the cake for an hour after frosting and serve
