This is a return to the classic Battenberg, a cake that is right up there in my list of top 5 cakes.
While I love to ring the changes with Battenberg cake, time and time again I get drawn back to coffee & walnut; for coffee & walnut cake is right at the top of my list!
One of the sponges here is coffee & walnut; the other is white chocolate & vanilla.
The buttercream is flavoured with salted caramel, dark chocolate and strong espresso: while I find instant coffee gives the better flavour for cakes, espresso in the buttercream, however, gives a wonderful intensity: but instant coffee in the buttercream works very well.
And I know salted caramel is somewhat ubiquitous but it deserves to be: it is quite quite fabulous!
I decorated the top with caramelised coffee walnuts (a little coffee boiled with the caramel): a sprinkling of sea salt crystals on the just-dipped walnuts gives very pronouncable salty crunch amid the sweetness: fantastic!
Making two different sponges
I use a square tin (20cm sides) and a greaseproof pleat down the middle to separate the two different cakes. They then get turned out, cooled and then trimmed to give two identically sized sponges.
The flavour variations are almost endless, but others that I love include:
Assembling a Battenberg
This is actually an easy affair and I have given images to demonstrate what to do with the recipe below.
A key tip: the buttercream needs to be very soft so that it does not tear the sponges or let too many crumbs escape. And with this in mind, I sometimes freeze the cake and buttercream it while it is frozen.
But the most important tip I can give is: when you trim the two ends, you get to eat them!!
Recipe: salted mocha & walnut Battenberg cake: makes one large cake (8-10 slices)
- 200g self-raising flour, sifted
- 200g caster sugar
- 200g unsalted butter or margarine, softened
- 4 large eggs, at room temperature, beaten
- 3 teaspoons instant coffee granules dissolved in 2 tablespoons boiling water
- 60g walnuts, chopped
- 60g white chocolate, chopped
- 1 teaspoon almond extract (optional)
- 80g unsalted butter, softened
- 140g icing sugar, sifted
- 3 tablespoons salted caramel sauce
- 3 tablespoons strong espresso coffee, cooled (or use instant coffee dissolved in boiling water and cooled)
- 50g dark chocolate (at least 70% solids), melted and cooled
- 400g good quality marzipan
- icing sugar for rolling out and dusting
- walnut pieces (dipped in caramel if preferred and sprinked with sea salt)
- a little of the buttercream to stick the walnuts to the top of the cake
(1) Pre-heat the oven to 160C (fan) and grease a 20cm square cake tin, and line with a large sheet of greaseproof that has been folded to form a pleat. The greaseproof should be positioned so that the pleat is in the centre of the tin (see diagram below step 4).
(2) Mix together the butter and sugar in a large bowl for a few moments to incorporate them. Add eggs and the flour, and gently mix together until just incorporated: don’t overbeat otherwise you will get heavy sponges. Split into two identical portions, each of which will become the two different sponges.
(3) For the coffee and walnut sponge, mix the coffee liquid and the chopped walnuts into one of the portions of cake mixture. Pour into one half of the tin and flatten out. (The remaining coffee liquid will be used to flavour to buttercream).
(4) For the other sponge: mix the almond extract (if using) and the chocolate with the remaining cake mixture and pour into the other half of the tin, flattening out (as in the diagram below).
(5) Bake for about 25-30 minutes until golden-brown on top and cooked through (a skewer inserted into the cake comes out clean). Leave the cooked cakes in the tin for a few minutes and then carefully invert onto a wire rack to cool. Although the colour of the cake surfaces might not look too different, when they are cut you will see the colour difference very clearly.
(6) To make the buttercream: beat the butter and icing sugar for a few minutes until very soft and creamy. Add the espresso, salted caramel and melted dark chocolate and beat well to give a light buttercream. Taste, and add more coffee or salted caramel if you prefer: you certainly want these flavours to come through.
(7) Remove the greaseproof carefully from the cake and place one cake on top of the other. Trim the long edges to neaten them and cut each cake in half length-ways, giving 4 uniformly sized strips of cake. The shorter edges can be trimmed once the marzipan is wrapped around.
(8) Stack the 4 strips of cake in a 2-by-2 arrangement just so you can measure the perimeter around the short edge with a tape measure or string. It should be a bit more than 30cm.
(9) Roll out the marzipan thinly to a rectangle that is a little more than 30cm by 20cm (ie: the width perimeter of the 2-by-2 cake stack and the length of the cake, respectively). Spread some of the buttercream over the centre of the marzipan.
Assemble the Battenberg:
The details are given below, along with several photos of each stage
(10) Assemble the sponges by placing one piece of sponge on the buttercream, sticking the other flavour sponge to this with more buttercream. Spread buttercream over the top and repeat with the other two sponges, making sure you alternatate the flavour. Push the sponges together firmly so that they hold their shape and spread buttercream along the sides; it doesn’t matter if the icing is not too smooth.
(11) Lift the left “flap” of marzipan over the cake, patting well down against the buttercream. Now lift the remaining “flap” of marzipan over the cake, also patting it well down against the buttercream. Push together any overlap of marzipan and place cake on a plate, seam-side down. Gently flatten the sides so that you have a clear “brick” shape.
(12) With a sharp knife, trim the shorter faces of the cake. It is now ready to serve just as it is, but if preferred you can lightly score the surface of the cake diagonally, pinch the marzipan to crimp the long edges, top with walnuts (using the remaining bit of buttercream to stick these to the marzipan if preferred)