Ultimate chocolate cake: devil's food layers, chocolate pudding filling, whipped ganache and drip glaze

Pour boiling water over the cocoa powder, add milk to bring the temperature down, whisk smooth and set aside.

Cream 9 oz room-temperature butter with 3 cups sugar until it goes from pale yellow to almost white; add vanilla.

Add the five room-temperature eggs one at a time so the batter emulsion does not break; mix evenly.

Alternate additions of the cocoa mixture and the dry ingredients (all purpose flour, salt, baking soda, baking powder); do not overmix.

Grease the pans with non-stick spray and coat with cocoa powder.

Divide the batter with an ice cream scoop, about 10 scoops per pan, and spread it flat.

Bake at 350 for 35 to 40 minutes, until a toothpick in the very centre comes out clean.

Pudding: warm milk and a little cream over medium heat with unsweetened and bittersweet chocolate, stirring constantly until melted.

Mix the cornstarch into the granulated sugar to prevent clumping; add a pinch of salt. Add the egg yolks only when ready to cook.

Whisk the egg yolks into the sugar mixture, then whisk in about a third of the hot chocolate milk; pour it back into the pot while whisking constantly.

Cook, whisking, then switch to a spatula as it thickens; bring to first boil, a big bubble from the centre, so the enzyme in the yolks is destroyed.

Off the heat, stir in 2 tbsp butter and vanilla; strain if wanted, cover directly with plastic wrap and chill until cold.

Whipped ganache: pour simmering cream over finely chopped bittersweet bar chocolate, let sit, then stir from the centre outward until smooth; leave at room temperature to firm up.

Glaze: bring a smaller amount of cream to a boil, pour over chocolate and stir from the centre the same way.

Split each cake in half to make four layers; whip the firmed ganache in the mixer until light and thickened.

Start with a bottom layer, pipe a ring of whipped ganache at the edge, fill with about four scoops of pudding and smooth the top; repeat, finishing with a layer flat side up.

Pipe whipped ganache around the outside, press it in with a spatula as a thin crumb coat, and smooth a thin layer on top.

Refrigerate about 15 minutes until cold, then move the cake to its stand.

Warm the glaze until fluid; spoon it at the edge and nudge drips over in varied lengths, then spread more on top.

Pipe the remaining whipped ganache in decorative effects and finish with dark chocolate, milk chocolate and gold sprinkles.