Chocolate genoise with raspberry buttercream

Sun, 12 April, 2015

• For the chocolate genoise:
• 70g plain flour
• 20g cocoa powder
• 3 eggs
• 1 egg yolk
• 90g caster sugar
• 30g butter
• For the raspberry buttercream:
• 100g raspberries, fresh or frozen
• 100g butter, softened
• 185g icing sugar
• 2 tsp double cream
• For the chocolate frosting:
• 100g good quality dark chocolate, 70% cocoa
• 300ml double cream
• 2 tbsp. icing sugar

METHOD

1. Preheat the oven to 180C/350F/gas 4. Prepare a round 20cm tin by buttering and flouring it thoroughly. Place a disk of parchment at the bottom. Mix the flour and cocoa powder and sieve it 2 or 3 times.

2. Prepare a pan with hot water – or bain-marie – large enough to contain the bowl you will be making the batter in. Break the eggs and the egg yolk into the bowl placed in hot water or over bain-marie and beat on low speed with a hand-held mixer until the eggs become foamy. Add the sugar, little by little. Keep beating on low speed until the eggs warm up slightly – to just about body temperature.

3. Take the bowl out of the water and beat in a standing mixer (with a balloon attachment), or continue with hand-held, at high speed for about 5 minutes, then medium speed for another 5 minutes. They should inflate to about five times their original volume, turn pale and form ribbons when the mixer paddle is removed.  Sieve the flour and cocoa mix over the egg mix from high above in two or three goes folding it in very gently each time before sieving in more. Make sure the mix does not deflate. Then get a heaped spoonful of the batter and mix with the warm butter, then fold it gently back in.

4. Pour the batter into the tin and twist it sharply to remove large air bubbles. Bake for 25-30 minutes until the sponge crackles slightly when pressed with a finger and leaves a small indentation.

5. Take out and drop from 20cm height onto a couple of folded tea towels, two or three times. This is the fun part, and it works so well it’s amazing – contrary to appearance, it stops the sponge from collapsing and sinking. Turn the tin upside down onto a wooden board and leave for 5 minutes. Turn it the right side up, remove from the tin and cool completely on a cake rack.

6. Prepare the raspberry puree: if using frozen raspberries, thaw them completely in a sieve placed over a bowl. Discard the liquid dripped into the bowl, then pass the raspberries through the sieve with a bottom of a large spoon until very little pulp and seeds remain on the sieve, scrape the bottom of the sieve several times whilst doing it.

7. To make the buttercream, beat the butter until pale and fluffy. Still beating, add the raspberry puree by a spoonful and the icing sugar by a couple of spoonfuls. Reserve a little puree to spread on the cake halves. At the end add the cream and whisk in. If you’ve been generous with the puree the buttercream might curdle slightly – adding a bit more icing sugar might save it but anyway this won’t affect the taste and the filling goes inside not on top of the cake so it won’t be too unsightly.

8. Prepare the chocolate frosting: break the chocolate into small pieces into a bowl and add the icing sugar. In a small pan bring the double cream to the boil and pour it boiling over the chocolate. Leave to stand for a couple of minutes and then stir it well. Leave to cool completely, then place in the fridge for at least half an hour.

9. Whip the chilled chocolate mix with a hand or in a standing mixer with a balloon attachment until it thickens, lightens in colour and has a mousse consistency – don’t over-whip.

10. Assemble the cake: slice the genoise horizontally using a cake slicing wire, a very sharp knife or a cotton thread (make a shallow incision with a sharp knife along the edge, halfway through its height. Take a length of cotton thread and wrap around the cake, fitting it into the incision. Twist the thread as if you wanted to strangle the cake until it cuts through).

11. Place the two halves on a board, cut sides up. Spread the reserved raspberry puree on both halves, pipe or spread the raspberry buttercream over the bottom half, slide the top layer onto the filling and press gently all around with your hand, until the filling shows up at the edges.

12. To frost the cake you can either simply slather the chocolate frosting over the top and the sides with a palette knife. Alternatively stuff the frosting into a piping bag with a star shaped nozzle and pipe little rosettes all over the cake including the sides. Chill in the fridge, grate some white chocolate over the top if you fancy.

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See also

Dome cake

Genoise with blueberry filling

Raspberry cream roulade