Tuesday, 30 August 2016

GBBO 2016 - Week 1 - Chocolate Pecan Mirror Glaze Cake

Bake Off is back!!! Last week the first episode aired, and it was even better than I hoped. The technical challenge were Jaffa cakes, which I obviously loved (my last post was a Jaffa cake inspired cheesecake). The showstoppers really took my breath away though - shiny delicious mirror glaze cakes. A lot of the bakers really impressed, but I particularly liked the idea of Benjamina's white chocolate and pecan mirror glaze cake. Genoise sponge layers, filled with white chocolate and pecan meringue buttercream filling, and topped with a white chocolate mirror glaze. I couldn't find a recipe for white chocolate mirror glazes, so instead made a dark chocolate one, and wow it tastes good, and looks even better. 

My decoration came from a bit of a disaster...I used a template whilst spraying gold onto the cake, and it got stuck to the glaze...to rectify, it's become a tree, and looks pretty good I think :)

Makes one 20cm cake


For the genoise sponges:

  • 40g (3 tbsp) butter, melted
  • 5 eggs
  • 165g (3/4 cup) caster sugar
  • 165g (3/4 cup) self-raising flour

For the white chocolate pecan filling:

  • (1/4 cup) caster sugar
  • 1 egg white
  • 130g (1 stick and 1 tbsp) butter, softened
  • 20g (1 oz) white chocolate
  • 1/2 tsp vanilla extract
  • 75g (1/2 cup) chopped pecans

For the chocolate ganache crumb coating:

  • 100g (2/3 cup) milk chocolate
  • 100g (2/3 cup) dark chocolate (50% cocoa solids)
  • 150ml (2/3 cup) double cream

For the mirror glaze:

  • 1 gelatine leaf
  • 75g (3/4 cup) cocoa powder
  • 120g (5/8 cup) caster sugar
  • 60ml (1/4 cup) water
  • 1 tbsp golden syrup
  • 60ml (1/4 cup) single cream

To decorate:

  • Edible gold spray
  • Handful of pecans, roughly chopped


1. Make the genoise sponges. Preheat the oven to 180c/350f/gas mark 4. Grease two 20cm loose-bottomed cake tins, and dust the base and sides with flour (I find this gives a better result than lining with baking paper).

2. Half fill a saucepan with water, place on a medium heat and bring to a simmer. In a large heat-proof bowl (large enough to sit on top of the saucepan WITHOUT touching the water), add the eggs and caster sugar. 

3. Place the bowl on the saucepan, and use an electric whisk to beat the eggs and sugar for 7 minutes, until the mixture has tripled in volume, and a trail of mixture is visible for a few seconds after lifting the whisk from the bowl. 

4. Remove the bowl from the heat. Sieve the flour into the cake mixture, one third at a time, and gently fold in using a metal spoon. Gently pour in the melted butter around the side of the mixture, and fold in.

5. Pour into the prepared cake tins. Bake for 18-20 minutes, until golden and springy to the touch. Set aside to cool.

6. Make the filling. In a large heatproof bowl add the egg white, caster sugar and vanilla. Place over a saucepan of simmering water, and heat for 5-7 minutes, until either a thermometer reads 140c, or the egg mixture feels hand-hot.

7. Remove from the heat, and continue whisking until stiff peaks form. 

8. Melt the white chocolate in a microwave by heating for 10-15 second bursts, and stirring well each time.

9. Add spoonfuls of the butter mixture to the egg whites, whilst continuing to whisk. Once all of the butter has been added, pour in the white chocolate and chopped pecans, and stir in. Cover and place in the fridge to firm up for 20-30 minutes.

10. Make the crumb coating. In a saucepan heat the cream until it is bubbling. Meanwhile, chop the chocolate into chunks and tip into a bowl.

11. Once the cream is bubbling, take off the heat and pour onto the chopped chocolate. Stir until all of the chocolate has melted. Cover and refrigerate for 20-30 minutes.

12. Make the mirror glaze. Soak the gelatine leaf in a bowl of cold water for 5 minutes, until it is very soft.

13. Heat the sugar, water and golden syrup together in a saucepan. Once the sugar has dissolved, leave to boil for 2-3 minutes.

14. Take off the heat and add the cocoa powder. Whisk until smooth. 

15. Add the single cream, whisk in, then return to the heat for a for a minute, stirring continuously.

16. Squeeze the excess water out of the gelatine, and add to the saucepan. Take the pan off the heat, and whisk until the gelatine has dissolved (this should only take a few seconds). Set aside.

17. Assemble the cake. Place the first half of the cake onto a board. Add the white chocolate filling to the top of the layer, and smooth over.

18. Place the second cake layer on top of the first, and press down lightly.

19. Gently smooth the chocolate ganache all over the top and sides of the cake. The sponge is delicate so be careful not to break it. Smooth the ganache as well as much as possible.

20. Heat the mirror glaze on a low heat until it is runny. Pour over the top of the cake, and with a knife carefully work the glaze over the sides of the cake so that the top and sides are covered. Place the cake in the fridge to firm up for about 20 minutes.

21. Decorate the top of the cake with gold spray and chopped pecans.

22. Enjoy!

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  1. It looks lovely, but so long as it tasted sublime. Could one use other types of gelatin than leaf, and, would leaf gelatin be the same as Asian seaweed gelatin? Is your gelatin animal of vegetal?

    1. It really did taste awesome! My only regret is that I didn't take a picture of the cake when a slice had been taken :O The gelatine I use is from pork. I think a vegetarian substitute such as agar agar (seeweed gelatine) would work - according to some research I've done, 1 tsp of agar agar would be equivalent to 1 tsp powdered gelatine (animal), which roughly converts to 1 sheet of gelatine. I haven't tested it myself, but that should work. Let me know how it goes if you try it :)