Opera cake | Classic french opera cake | 10 layers cake

Preparation time : 1 hour 30 minutes + chilling time 

Baking time : 16-20 minutes

Cooking time : 20 minutes

Baking tray : 13*14 inches *2 

Ingredients :

* Almond sponge cake :

• Eggs - 8 ( room temperature )
• Almond flour - 220 grams
• Powdered sugar - 220 grams + 4 tbsp
• All purpose flour - 60 grams
• Unsalted butter - 60 grams
• Salt - 1/2 tsp
• Egg whites - 8

* Espresso syrup :

• Water - 160 ml
• Sugar - 1/2 cup
• Instant coffee powder - 4 tsp

* Choco hazelnut crunch :

• Dark chocolate - 140 grams
• Hazelnuts - 150 grams
• Whipping cream - 6 tbsp

* Chocolate ganache : 

• Dark chocolate - 320 grams
• Whipping cream - 320 grams

* Coffee buttercream :

• Unsalted butter - 400 grams ( softened )
• Icing sugar - 800 grams
• Vanilla extract - 1/2 tsp
• Instant coffee powder - 6 tbsp
• Boiling water - 3 tbsp

* Chocolate glaze :

• Dark chocolate - 400 grams
• Canola oil - 4 tbsp

Method : 

* Almond sponge cake :

1. Preheat oven to 200 degrees Celsius. Grease and line with parchment paper to baking tray.
2. Take egg whites and salt in a bowl, whisk until foamy.
3. Gradually add 4 tbsp sugar and continue whipping until stiff peaks.
4. Take a large bowl, add sieved almond flour and powdered sugar. Mix well.
5. Add eggs and whisk until the mixture is creamy and fluffy.
6. Gradually add all purpose flour. Mix well.
7. Fold the whipped egg whites into the almond mixture in batches.
8. Add melted butter. Mix well.
9. Divide the batter evenly into two prepared trays.
10. Bake for 8-10 minutes or until slightly golden on top.
11. Cool completely and cut into half and keep aside.

* Espresso syrup :

1. In a sauce pan, add water, sugar and coffee powder.
2. Bring to boil over medium heat. 
3. Set aside to cool completely.

* Choco hazelnut crunch :

1. Dry roast hazelnuts. Crush into coarse.
2. Melt chocolate on double boiler. Whisk till melted (remove from flame).
3. Add whipping cream and crushed hazelnuts. Mix well.
4. Take one sheet of sponge cake. Gently spread choco hazelnut crunch and refrigerate till set (preferable overnight).

* Chocolate ganache :

1. Place chocolate in a bowl.
2. Heat whipping cream in a small sauce pan, until it starts to boil. 
3. Pour over the chocolate. Let it set for 1 minute. Stir until completely melted. 
4. Set aside to cool at room temperature.

* Coffee buttercream :

1. Mix instant coffee with boiling water. Set aside to cool.
2. Cut butter into cubes and then beat on low medium speed until soft. 
3. Gradually add the icing sugar and beat until fully combined.
4. Add vanilla extract and gradually add coffee mix 1 tsp at a time. 
5. Whisk well until soft, smooth and fluffy.
6. Check the consistency of buttercream. It should be soft and perfect for piping at this point. if its too stiff the beat in a little milk.

* Cake assembly :

1. Take choco hazelnut crunch sponge layer, flip on a serving plate or cake board with choco crunch facing down.
2. Brush the sponge cake with espresso syrup.
3. Spread half of the chocolate ganache.
4. Place second layer of sponge cake. Brush with espresso syrup.
5. Spread coffee buttercream. Place the third layer of sponge cake. Again brush with espresso syrup. 
6. Spread the remaining chocolate ganache. 
7. Place fourth layer of sponge cake. Brush with espresso syrup.
8. At the top spread the coffee buttercream on top and sides. Even the surface using an spatula.
9. Cover and refrigerate the cake for at least 2 hours or even overnight.

* Chocolate glaze :

1. Melt the chocolate over double boiler. add oil and stir to combine.
2. Pour the glaze immediately over the chilled cake to create a smooth surface.
3. Refrigerate for about 1 hour to set.
4. Smooth the dripping on the bottom of the cake.
5. Using a hot knife cut the edges of the cake. 
6. Pipe the remaining coffee buttercream and decorate as per your choice and preference. 
7. Slice and serve.

Video :

Step by step pictures of making opera cake : 

Preheat oven to 200 degrees Celsius 

Take egg whites in a bowl 

Add salt 

Whisk till foamy 

Gradually add 4 tbsp powdered sugar

Continue whipping until stiff peaks 

And keep aside 

Take a large bowl, add sieved powdered sugar 

Add almond flour 

Mix well  

Add eggs 

Whisk until the mixture is creamy and fluffy 

Gradually add all purpose flour 

Mix well 

Fold whipped egg whites into the almond mixture in batches 

Mix well 

Add melted butter 

Mix well 

Grease and line with parchment paper to baking tray 

Divide the batter evenly into two prepared trays 

Spread evenly 

Bake for 8-10 minutes 

Until slightly golden on top 

Peel off the parchment paper 

Cool and cut into half 

Keep aside 

Add water in a sauce pan 

Add sugar 

Add coffee powder 

Mix well 

Bring to boil and set aside to cool completely 

Melt chocolate on double boiler

Whisk till melted and remove from flame 

Add whipping cream 

Whisk well 

Add dry roasted and crushed hazelnuts 

Mix well 

Take one sheet of sponge cake. Gently spread choco hazelnut crunch

Spread evenly 

Cover and refrigerate till its set (preferable overnight) 

Place chocolate in a bowl 

Heat whipping cream in a small sauce pan, until it starts to boil

Pour over the chocolate 

Let it set for 1 minute 

Stir until completely melted 

Set aside to cool at room temperature 

Mix instant coffee with boiling water 

Mix well 

Set aside to cool 

Cut butter into cubes 

Whisk on low medium speed until soft

Gradually add icing sugar 

Beat until fully combined 

Add vanilla essence 

Gradually add coffee mix 1 tsp at a time

Whisk well until soft, smooth and fluffy 

Check the consistency of buttercream, it should be soft and perfect for piping 

Take choco hazelnut crunch sponge layer 

Flip on a serving plate or cake board with choco crunch facing down 

Brush with espresso syrup 

Spread half of the chocolate ganache 

Place the second layer of sponge cake 

Brush with espresso 

Spread coffee buttercream 

Place third layer of sponge cake 

Brush with espresso 

Spread the remaining chocolate ganache 

Place 4th layer of sponge cake 

Brush with espresso 

Spread coffee buttercream 

Cover the sides 

Cover and refrigerate the cake for at least 2 hours or even overnight 

Melt chocolate over double boiler 

Melt till its smooth 

Add oil 

Stir to combine 

Pour immediately over the chilled cake 

Spread evenly 

Refrigerate for about 1 hour to set 

Heat the knife well 

Trim off the edges 

Now its ready to decorate 

Pipe the remaining coffee buttercream 

Decorate as per your choice 

Slice and serve