Keith's "Dad's Chocolate Orange" Vertical Layer Cake

Total Time:

5 hours

Serves:

Serves 10

This dish requires making more sponge than is actually needed for the cake, but the excess freezes well and can be used in a trifle or even in a bread and butter pudding.

Ingredients

CHOCOLATE SPONGE
160g butter
12 eggs, separated
1.25 cups milk
60g all-purpose flour
60g vanilla powder
120g cocoa powder
300g caster sugar

ORANGE SPONGE
120g butter
9 eggs, separated
Zest and juice of 4 oranges
210g all-purpose flour
30g vanilla powder
220g caster sugar

ORANGE BUTTERCREAM
350g butter, softened
600g powdered sugar
Zest and juice of 2 oranges

CHOCOLATE GANACHE
100g butter
200g powdered sugar
100g cocoa powder
100g chocolate chips, high quality
1 cup heavy cream

Instructions

PREPARING THE TINS
Heat oven to 370ºF. In total this uses 3 rectangular chocolate sponges (8” x 12”), a pair of round (8”) chocolate sponges, and 3 rectangular (8” x 12”) orange sponges to assemble this cake. Prepare the tins with oil and powdered sugar and/or line with baking parchment. Most likely you won’t have enough tins to bake all the sponges in one batch, so expect several relays.


CHOCOLATE SPONGE
Melt the butter and whisk it together with the egg yolks and milk. Stir in the flour, vanilla powder and cocoa powder into the melted butter to make a paste. Whisk a little at a time until it is completely mixed and smooth.

Whisk the egg whites until stiff. Add the sugar and continue whisking until the mixture is glossy and thick. Whisk a third of the meringue mixture into the chocolate mixture to loosen, then use a big metal spoon to gently fold the remaining meringue into the batter. Spread the batter evenly in the rectangular and round tin(s). Bake for 12 mins.

Turn the cake(s) out of the tin onto a surface lightly dusted with powdered sugar. Remove all the parchment and eave to rest. For one of the rectangular sponges, very loosely roll it like a Swiss roll, starting from a short end. This will become the center of the cake and will need rolling tightly later.


ORANGE SPONGE
Repeat as for chocolate cake, but instead of milk, use orange juice and stir in the zest. Roll up one of the orange rectangular sponges in a loose Swiss roll.


ORANGE BUTTERCREAM
Beat together the butter, powdered sugar, orange zest and juice. Beat until just combined.


CHOCOLATE GANACHE
Put all the chocolate ganache ingredients in a bowl over a pan of barely simmering water. Gently melt together, stirring, until smooth and shiny.



ASSEMBLY
Cut each rectangular sponge (including the loosely rolled ones) into 2 long strips 3” wide – trimming the long edges off will give you a neater finish. It’s important to be really accurate, so use a ruler. Trim the short edges to neaten. When you prepare the rolled-up sponges, just gently unroll first – don’t worry if they crack a bit.

Spread a thin layer of orange buttercream over every strip, right to the edges. Start with 1 chocolate and 1 orange strip that was rolled up to cool, and lay one on top of the other – but don’t line up the starting ends. Sit the second sponge about an inch down from one of the ends of the bottom sponge (it doesn’t matter which is chocolate and which is orange).

Start to roll up from this end – the bottom sponge should roll up and over neatly on top of the second, so the middle of the roll is nice and tight. Move on to the second pre-rolled strips, again sandwiching together with buttercream and staggering the ends to keep the roll going

Keep adding extra sponges and rolling up to make a giant Swiss roll but as you roll, the ends of each different-colored layer won’t finish together. At some point it will be best to add the chocolate and orange sponges individually, rather than sandwiching together first. Where each strip ends, you’ll stick on a matching sponge – so a chocolate strip always continues with another chocolate, and the same with orange. This is the fiddly bit, not difficult, just detail-oriented.



Stop rolling when your giant Swiss roll is the same size as your round sponges which will be ‘caps’ top and bottom. Depending on how tightly you rolled the sponges, and the thickness of your filling, you may have some left over.



Sit the rolled cake on one of its flat ends. Spread a good layer of orange buttercream over the top, then press on 1 of the round chocolate sponges – line it up to the middle of the roll and if your roll is bigger than the lid, then trim the roll all around, until it is perfectly flush with the round sponge top. Flip the cake over, spread some more orange buttercream and top off with the second round sponge.



Completely smother with the chocolate icing, spreading with a big flat knife. If should still be runny enough to gently run down the sides, giving you a shiny finish, so re-melt it if necessary.