Lifechanging Brooklyn Blackout Cake

Steps

1. 1Preheat oven to 325F (no fan) and prepare 3 9" pans with parchment paper and butter.
2. 2In a bowl, combine the flour, baking powder, baking soda, granulated sugar, light brown sugar and salt. Whisk together until no lumps remain.
3. 3In a separate bowl, whisk together the eggs, vegetable oil, buttermilk and sour cream until smooth.
4. 4Add the dry ingredients to the wet in 2 additions, and gently whisk and fold until they are just combined and no big lumps remain. Do not overmix.
5. 5In a separate small bowl, add the cocoa powder and instant coffee. Pour over the boiling water and whisk until a smooth shiny mixture forms.
6. 6Pour the cocoa mixture onto the remaining batter, and gently fold until a chocolate cake batter forms.
7. 7Divide the batter evenly between the 3 prepared cake pans.
8. 8Bake for ~18-20 minutes until a toothpick inserted in the center comes out with light moist crumbs attached.
9. 9Let the cakes cool in the pans for 20 minutes, then carefully remove them and place on a wire rack. Let cool completely (I recommend refrigerating for 1 hour).
10. 10Add all ingredients for the pudding to a large nonstick saucepan.
11. 11Place on the stove on low heat, and use a whisk to gently stir and cook the pudding until the butter and chocolate melt and all ingredients combine. It will look strange and lumpy in the beginning but will come together as it cooks.
12. 12Keep cooking and stirring on low heat until the pudding comes to a boil. After this point, it will start to thicken up quickly. Keep an eye on it, and cook until the pudding reaches a thick, custard like consistency and starts to hold shape (if you run a spoon through it, it should leave a mark that doesn't dissolve). Remove from the heat. The total cooking time should be around 10 minutes.
13. 13Strain the pudding to remove any lumps. Pour it into a wide plate, cover with cling wrap, and refrigerate for at least an hour until cool and thick.
14. 14Add the chocolate and cream to a microwave safe bowl. Microwave in 20 second increments, stirring in between, until the chocolate has melted and a smooth ganache forms. Set it aside.
15. 15Add the cream cheese and sugar to a bowl. Whisk for 2-3 minutes, scraping the bowl along the way, until smooth.
16. 16Pour in the warm ganache, and whisk for 1-2 minutes until combined and the mixture starts to look fluffy. The frosting will be runny.
17. 17Place the frosting in the fridge for ~20 minutes, or until it thickens up into a spreadable consistency. Remove from the fridge at this point so it doesn't become too firm.
18. 18Once all components are cool, it's time to assemble. To start, use a sharp serrated knife to trim off the domes from the cake layers so they become completely straight. Place the cake trimmings into the freezer so you can grate them for decoration later.
19. 19Transfer the frosting to a piping bag. Place a cake layer onto a turntable or cake stand, and pipe a thick ring of frosting around the edges. Make sure there aren't any gaps in this ring. Then spoon half of the chocolate pudding onto the cake and spread it evenly, such that the ring of frosting holds the pudding inside and doesn't let it leak out.
20. 20Cover with the next cake layer and repeat. Then cover with the last cake layer, and frost the cake with the frosting all over (you don't need to do a crumb coat for this cake as it gets covered in crumbs anyway). If at any point it feels like the cake layers are sliding around or the pudding is leaking out, quickly wrap the cake tightly in cling wrap and place in the fridge to firm up.
21. 21Remove the cake trims from the freezer and use a zester or fine grater to turn it into fine crumbs. Fill your hand with cake crumbs and press it against the side of the cake so the crumbs can stick to the frosting. Repeat until the cake is coated in crumbs on the sides.
22. 22Place in the fridge for at least 1 hour so the cake and pudding can properly set. Then slice, serve and enjoy!