Mirror Glaze Cake – GBBO Showstopper Challenge (Week 1)

So, who here watches The Great British Bake Off? I’m guessing everyone, right?

Well, as you probably know, the new series started last Wednesday and I could not be happier to have it back in my life again! I don’t know what it is about watching people bake a cake under pressure that makes millions of people turn on their television screens every week, but I’m not ashamed to say I’m one of them!

I’ve watched this show religiously since the beginning and have learned sooooo much about cake, biscuits and soggy bottoms over the years! It’s definitely helped me discover my love of baking, and this year I decided to up my baking game.

This year, I figured why not put myself in the bakers shoes and challenge myself to make the Showstopper Challenges from each episode? To the judges criteria, and in the given time limit. Because I clearly like to make things difficult for myself!

Therefore, each week I plan to write a post documenting my progress, whether successes… or failures…

Lemon Genoise Sponge. Blackberry Buttercream. Fresh Blackberries. Galaxy Mirror Glaze. What’s not to love?

• 4 sheets of gelatine
• 125ml water
• 200g sugar
• 150g chocolate
• 60ml double cream
• 30g cocoa powder

First I soaked the gelatine leaves in cold water.

Then I added the sugar and the 125ml of water to a large saucepan and left this to bubble until it reached 104°C. Once it reached this temperature I removed it from the heat.

To a large heatproof bowl I poured in the cream and snapped the dark chocolate into smaller pieces. I then poured the hot sugar on top, let sit for a minute then whisked thoroughly.

Finally, I sieved the cocoa powder into the mixture, and added the gelatine leaves (making sure to squeeze out any excess water) before whisking to combine.

To help everything melt/dissolve I also used a hand blender to blitz up any stubborn pieces of chocolate.

I even strained the glaze through a sieve to make sure it was completely smooth. So much effort, but totally worth it for such a sexy glaze!

I left the glaze to set up a little  (so it held it’s form for a few seconds when drizzling, and didn’t flow too quickly). Once I was happy with the consistency, I placed a small test chocolate cake on a tall container placed on a large baking tray (to catch all the glaze), before pouring the glaze over the cake in circular motions to coat the entire cake.

https://www.instagram.com/p/BJv_iZiB6rC/?taken-by=wizmikal

I then used a toothpick to pop any air bubbles for an even finish.

I let the cake set up a little before moving to the fridge to chill entirely.

Happy with my first attempt at a mirror glaze, I then attempted the GBBO challenge as stated in the episode:

• Mirror Glaze
• Genoise Sponge
• 3hr time limit

I started with the lemon Genoise sponge, whisking the eggs and sugar till thick, pale and fluffy. This took a good 5 minutes ish.

I then sifted in the plain flour and added the salt and lemon zest. I gently folded this into the mixture, making sure there were no pockets of flour but trying not to stir out all of the air.

I squeezed the lemon juice into the cooled melted butter, then poured this into the cake batter and gently stirred to combine too.

I poured this into a lined cake tin and baked at 180°C for 20-25 minutes until golden brown. (The cake should spring back slightly when pressed.)

For the blackberry buttercream, I started by whipping the butter until light and fluffy. This also took a good 5 minutes with an electric mixer.

I then sifted in the icing sugar and beat this together.

I blitzed up the fresh blackberries with a hand blender, then strained through a sieve to reserve the puree. (I yielded about 6tbsp.)

I added this to the buttercream, along with the milk and beat this together so the colour was evenly distributed.

Once the cake was cool, I levelled the top then sliced it in half.

I then frosted the cake with the buttercream (adding fresh blackberries to the centre). Applying a thin crumb coat to entire cake, I let this chill/set up in the fridge before frosting the entire cake. I left this to chill in the fridge completely whilst I made the glaze.

For the galaxy glaze, I made a white chocolate mirror glaze – so I could use food colouring to make the colours for the galaxy.

As before, I added the white chocolate and gelatine to the hot sugar (omitting the cocoa powder), blended, then strained through a sieve to get a smooth glaze.

I spooned about 5tbsp of glaze into two bowls each, and coloured those purple and pink. I then separated the rest of the glaze into 2 more bowls and coloured those black and navy.

I poured these onto the cake, mixing between the colours and swirling to create a galaxy pattern. I used a palette knife to gently smear across the cake to merge the colours together. I then left the cake to set up.

Once set, I mixed a little edible silver dust with a bit of water and flicked this onto the cake to create the stars.

Overall…

How long did it take? I started at 11am and finished just after 2pm… so yup, about 3hrs. 😀 I even had time to do some washing up in between (not everyone has an endless supply of kitchen equipment at their disposal), take photos/videos. *hairflick* I mean, I did forget to take photos of a few stages… but we’ll overlook that. I certainly did.

What worked? The Genoise sponge, and the flavour combo. Win. Blackberries are so underrated!

What didn’t work? The food colouring I used wasn’t the greatest quality, so didn’t achieve the colour I wanted. Also, white chocolate is pretty temperamental… and I felt like the white chocolate glaze took a little longer to set to the right pouring consistency. Maybe chocolate quality?

Things to improve if I were to take this recipe to the tent? Maybe use a white food colouring first to achieve a brighter colour when adding the other colours? Test different brands of white chocolate too.

*****