Brooklyn Blackout Cake

Directions

For the Cake:

1. Position a rack in the middle of the oven and preheat to 350 ̊F/ 180C. Oil the sides and bottoms of two 9 x 3-inch/ 23 x 7.6-cm round cake pans. Line the bottoms with parchment circles. Do not oil the paper.
2. Place a wire mesh strainer over a large bowl. Add the sugar, flour, cocoa, baking soda, and salt to the strainer and stir with a wire whisk to sift the ingredients into the bowl. Whisk to aerate.
3. Whisk the water, oil, maple syrup, vinegar, vanilla, and chocolate extract (if using) in a separate medium bowl until emulsified. Pour into the dry mixture and whisk until the batter is smooth.
4. Divide the batter between the pans. Rotate the pans to level the batter and tap them lightly on the counter to eliminate air bubbles.
5. Bake on the middle rack for 30 to 35 minutes, or until the tops of the cakes are set, the sides have started to pull away from the pan, and a wooden toothpick or skewer inserted into the center comes out clean or with just a few moist crumbs.
6. Set the pans on wire cooling racks. After 5 minutes, run a thin knife around the sides of each cake to release the sides of the cake from the pan. Invert each cake onto a rack. Remove the pans and carefully peel off the parchment paper. It is fine to cool the cakes bottom side up.
7. When the cakes are completely cool, slide a 9-inch cardboard cake circle under each one. Wrap the layers with plastic wrap and refrigerate for about 1 hour, or until cold.

For the Pudding:

1. Sift the sugar, cornstarch, cocoa powder, and salt through a wire mesh strainer into a large saucepan. Stir the milk in slowly until the dry ingredients are moistened.
2. Cook over medium-high heat, whisking frequently, until the mixture begins to thicken and is close to a boil. Adjust the heat as needed to get a full boil, but don’t let it be so high that the bottom scorches. As soon as the pudding starts to boil, it will thicken to pudding consistency. Immediately lower the heat and boil gently for another minute, stirring frequently, with a silicone spatula, making sure you reach the bottom.
3. Remove the saucepan from the heat. Add the chocolate and stir with the silicone spatula until the chocolate is melted and incorporated. Stir in the vanilla.
4. Spoon the pudding into a bowl. Cover the surface with plastic wrap, making sure the wrap adheres to the pudding to prevent a skin from forming.  Refrigerate until cold before using or up to 24 hours.

Assemble the Cake

1. Use a long, serrated knife to slice each cold layer in half horizontally to make four layers. Crumble one of the layers into a food processor. Pulse the processor to make medium-size crumbs. Pour the crumbs into a bowl.
2. Line a rimmed baking sheet with parchment paper. Place one of the remaining three layers, still on the cake circle, on the baking sheet. Spread with a scant cup of the pudding. Place a second cake layer on the pudding, board side up. Remove the board and spread the layer with another scant cup of pudding. Slip the board under the last layer and invert it onto the cake. Spread with another scant cup of the pudding. Refrigerate the cake and remaining pudding for 20 minutes. It is easier to finish a cold cake.
3. Cover the sides of the cake with the remaining pudding. Sprinkle the top and sides of the cake liberally with the cake crumbs, completely covering the pudding. Pat the crumbs lightly to make sure they adhere. Use all the crumbs, even the ones that fall onto the paper.