Chocolate orange cake

Chocolate orange has always been one of those flavours I love, so I thought it's a nice once to get me back into baking. Though more work on piping is required. I hope the people who had given up chocolate for Lent will find this a worthy cake to attempt! 

Ingredients 
Chiffon sponge

• 3 large eggs (separate yolk and white)
• 105g plain flour
• 15g unsweetened coco powder
• 4g baking powder
• 100, 50g caster sugar (in separate bowls/container)
• 60ml vegetable oil
• pinch of salt
• 1 tsp vanilla extract
• 1 large orange (you need the zest and about 80ml orange juice)

1. Pre-heat oven to 160 degree C (or 140 fan)
2. You will need a 21cm round cake tin (DO NOT grease or line with parchment paper)
3. Mix the egg yolks and 100g caster sugar together and mix until smooth
4. Sift the flour and coco powder and baking powder and add to the egg
5. Add the salt and orange zest, mix ingredients together
6. Add a well in the middle of the batter
7. Add the vegetable oil and orange juice
8. Mix everything until smooth
9. Beat the egg white with electric whisk until foamy
10. Add 1 tbsp of caster sugar (from 50g container) at a time to the egg white
11. Whisk until the egg white forms stiff peaks
12. Put in 1/3 of egg white to the cake batter and gently fold it in
13. Add the remaining egg white in two batches to the cake batter and CAREFULLY fold it in
14. Pour the cake batter into the cake tin 
15. Run a large metal life slowly through the cake batter to remove large air bubbles
16. Bake for 40-45 minutes
17. Cool upside down on a wired rack (if the tin was greased, then it will just slip out of the tin)

Simplified chocolate mousse

• 100g dark chocolate (at least 70% coco)
• 50g caster sugar
• 400ml double cream
• 50g icing sugar

1. Heat 200ml double cream with caster sugar until boiling, remove from heat and let it sit for a minute to cool down slightly
2. Chop/break chocolate into small pieces
3. Add the hot cream to chocolate
4. Gently stir until chocolate has completely melted (chocolate ganache)
5. Allow it to cool down to room temperature
6. Whisk 200ml double cream with icing sugar until the cream forms soft peaks
7. Once the ganache is cool and thick, add the whipped cream to the ganache and fold it in gently

Tempering chocolate

It is easier to temper a slightly larger amount of chocolate (preferably more than 100g high quality chocolate about 70% coco).

1. For 100g dark chocolate
2. Melt 70g chocolate over simmering water or on low power in a microwave
3. Break/chop remaining 30g chocolate into small pieces
4. Test temperature of melted chocolate and make sure it is below 50 degree C
5. Add in the remaining chopped chocolate (which would rapidly cool down the chocolate) and stir until it has melted
6. This chocolate is practically good to use for most people at home, but to make it better, the following optional step can be added
7. (Optional) To make sure the melted chocolate has a higher proportion of seed crystal (it has a higher melting point and provides the crisp and harder texture to the chocolate), re-heat the melted chocolate until it reaches 31-32 degree C
8. (Optional) This additional step melts chocolate crystal that is NOT seed crystal (lower melting temperature). The seed crystal in the melted chocolate would promote the other chocolate to take on the seed crystal structure and hence reduce the non-seed form
9. Test the consistency of chocolate by dropping a amount onto a parchment paper using a teaspoon, if it spreads, then it is too runny to be piped
10. Once the chocolate forms a more or less firm dot when dropped onto the parchment paper, then it is ready for piping into various shapes

Assembling

1. Slice the cake horizontally in half
2. Spread about 1/3 of chocolate mousse in the middle of the cake
3. Pipe/spread the rest of the mousse on the side and top of the cake
4. To decorate the top with orange slices, cut orange into thin slices and drain off the excess moisture with a clean kitchen cloth 
5. Place orange slices on top
6. Decorate with chocolate decoration