Blackcurrant, lime & vanilla Angel Cake slices

With the return of Great British Bake Off, it is the Technical round that interests and excites me the most. This is my tangy take on Episode 1’s Angel Cake slices.

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Difficulty-wise, this is a challenging and somewhat involved bake, not least getting the light sponge and dealing with 3 different flavoured sponges…not super-hard, but more of a faff!

But once ingredients are weighed out and portioned off into small bowls, it is just a matter of working through systematically – and it doesn’t take that long.

It actually all comes together in a calm manner. At least, it does in the home kitchen: I can, of course, empathise with the bakers making this recipe under the time restraints and other pressures with cameras on all the time!

Fruity flavours

You can go for whatever flavours you like for the layers. In Prue Leith’s Technical, the Angel Cake layers were flavoured lemon, vanilla and raspberry but I fancied a bit more oomph so went for blackcurrant, lime and vanilla: I had some blackcurrant powder that needed using up so it fit the bill here!

In the absence of an official recipe for the Technical, I went on the description given in the show: Genoise sponge recipe, Italian meringue buttercream and fondant icing, and made my go-to recipes for each.

The ideal sponge and buttercream

The sponge here is genoise: it has a much lighter, melt-in-the-mouth texture than a Victoria Sandwich sponge.

Italian meringue buttercream is luscious here to sandwich the layers together, but you can make a standard buttercream if you prefer.

I have made Angel Cake slices before using a Victoria Sandwich mixure and it tastes great. It is also less of a faff dealing with the Victoria Sandwich mixture when it comes to colouring and flavouring each layer!

Genoise sponge 3 ways!

The sponge is essentially eggs and sugar that gets whisked up over hot water until it becomes very voluminous and moussey. You then fold in very gently the flour, butter and any colours/flavours. You have to work carefully so that you don’t beat out the air whisked into the sponge mixture, otherwise you can end up with a dry, rubbery sponge.

As this mixture needs flavouring and colouring 3 ways, once the eggs and sugar have been whisked up you then split this plain mixture into 3 for flavouring and colouring separately, before then folding in both the butter and flour separately.

If you fold in all the flour and butter first before then splitting in three to add the flavours and colours, you risk over-working the mixture.

Of course, you could simply make 3 small batches, one at a time, and flavour/colour as you go, but the method below is quicker.

Genoise top tips

• the bain-Marie method for whisking the egg/sugar not only gives the best volume, it gives a more stable, forgiving  mixture so that when you fold in the flour, there’s less risk of collapsing.
• don’t rush the folding as the mixture will wait quite happily.
• use a large metal spoon for folding, not a spatula. The spoon is more effective.
• pour the melted butter around the edge of the mixture before folding, not on top of the mixture: if you pour it on top, it will start to collapse the mixture.
• use slow, gentle folding, making sure you scrape down to the base of the bowl where flour can often lurk!

Recipe: blackcurrant, lime & vanilla Angel cake slices – makes 6

Genoise sponges

• 60g unsalted butter, melted and cooled
• 4 large eggs, at room temperature
• 120g caster sugar
• 120g plain flour, sifted
• 1 teaspoon vanilla bean extract
• 2 teaspoons blackcurrant powder with a little purple food colouring
• grated zest of 2 limes with a little green food colouring

Italian meringue buttercream:

• 80g caster sugar
• 3 tablespoons cold water
• 2 large egg whites
• 120g very soft unsalted butter
• 1 teaspoon vanilla extract

Fondant icing

• 250g fondant icing sugar
• lime juice to mix (about 1 lime)
• a few drops of purple food colouring
• 1 teaspoon blackcurrant powder

You will also need three 1lb loaf tins, brushed with oil or melted butter and  lined with greaseproof

Sponges:

(1) Pre-heat the oven to 160°C (fan) and sieve the flour. Divide the flour equally into 3 small ramekins/cups. Stir the blackcurrant powder into one of them.

(2) Divide the melted butter equally between 3 small ramekins. Stir the purple colouring into one of then; the green colouring and lime zest into the other and the vanilla into the third.

NB: this might seem a lot of ramekins but it really makes life so easy when it comes to flavouring each sponge. It is also easier adding the food colouring to the a liquid ie) the melted butter – if you leave to mix at the end, you need a lot of folding to get the colour to incorporate, whereas you want minimal folding.

(3) Put the eggs and sugar into a medium heatproof bowl and place over a pan of barely simmering water, making sure the base of the bowl is not touching the water. Use an electric handwhisk and whisk on a high speed for about 6-7 minutes or until the mixture has increased significantly in bulk (between doubled and trebled), very pale and thick enough to hold a trail when the beaters are lifted.

NB: this mixture will hold it shape nicely so there is no need to rush the next stages.

(4) Divide the egg and sugar mixture equally between three medium bowls. Take one of the flours and sift it over one of the bowls containing the egg mixture. Fold in gently, keeping in as much air as you can. Finally, very carefully fold in one of the melted butters*. Pour this cake batter into one of the loaf tins.

NB: for these flavours, the purple butter with the flour that has the blackcurrant powder and so on.

(5) Repeat with the other flours and butter. Lightly flatten the surface of each and bake for 10 minutes until golden and slightly shrunk from the sides of the tin.

(6) Leave the sponges to cool slightly in the tins for about 5 minutes, then transfer to a wire rack to cool.

for the Italian meringue Buttercream

(1) Put sugar and water on a pan and heat gently, stirring gently to dissolve the sugar. Bring to the boil for about 5 mins over a medium heat until slightly thicker and syrupy.

(2) Whisk the egg whites until soft peaks form with a hand-held whisk and then slowly pour in syrup as you keep whisking on high speed. Whisk for about 5 minutes or until the merignue has thickened and cool.

(3) Whisk in the butter, a bit at a time, followed by the vanilla.

For the icing

(1) Mix the icing sugar into a medium bowl and add enough lime juice to form a fairly thick but spreadable icing.

(2) Remove about a tablespoon of the icing and mix in the blackcurrant powder and purple colouring. Spoon into a piping bag with a fine round nozzle.

ASSEMBLING THE CAKE

(1) Remove the greaseproof from the sponges carefully.

(2) Sandwich together the 3 sponges with the buttercream, lightly patting down each sponge as you add it. Spread a very thin layer of the buttercream on top. Chill until you are ready to ice the top.

NB: chilling the cake fully really makes the cake much easier to ice and slice. 

(3) Spoon the uncoloured fondant icing on top of the cake and lightly ease to the edges. Don’t worry if some of the icing drips over the edge: once the icing has set the drips will lift away easily – if you want to remove them that is! Or you can trim the edges before portioning the cake.

(4) Drizzle or pipe the blackcurrant fondant over the top or decorate it in any way you like. Leave the icing to set for at room temperature for at least an hour before cutting into 6 pieces: a sharp knife, dipped in hot water helps prevent the icing from wrinkling.