Old Fashion Chocolate Buttercream Cake

Chocolate Rice Flour Chiffon Cake 
Ingredients : for  8" square cake pan
5 egg yolks
10g caster sugar
40g corn or sunflower oil
1/8 tsp salt
40g cake flour
20g cocoa powder
30g rice flour 在来米粉/粘米粉
70g chocolate milk

5 egg whites
50g caster sugar
a few drop of lemon juice

Method :
1. Sift cake flour, cocoa powder and rice flour twice.
2. Mix egg yolks and sugar in a bowl, whisk till sugar has dissolved.
3. Add in oil, salt and chocolate milk and mix well.
4. Sift in flour mixture and whisk well.
5.In another bowl, beat the egg whites and lemon juice/vinegar till frothy. Add in sugar gradually and beat until approaching stiff peaks (meringue stand straight with a little curve at the tip) or till stiff peaks (this stage is a bit difficult to fold with egg yolk mixture).

6. Use whisk to loosen the egg yolk batter a bit, then take 1/3 of meringue and use a hand whisk to mix well with egg yolk batter.

7. Fold in 1/2 of meringue and use a silicone spatula, gently fold with egg yolk batter till slightly combined. Fold in the balance meringue and gently fold till well combined.
8. Pour the batter from a considerable height into cake pan, lightly shake it left and right to level the cake, then gently bang the cake pan on the table top to release air bubbles. 

9. Bake at pre-heated oven at 100C at center rack for 25 mins and 160C for 15-20 mins. (I off the top heat element and on it back during the last 15 mins)

10. Remove the cake pan from oven, drop it from high side to prevent the cake shrink too much during cool process.

11. Turn the cake pan upside down and cool completely before remove from the cake pan. 

French Buttercream : adapted from Table for Two or More..

100g sugar
75g water
4 egg yolks (100g), room temp
250g unsalted butter, cold 
1/2 tsp vanilla extract 

200g couverture chocolate, melted

Method :
1. Cook water and sugar in a heavy based saucepan on medium heat. Gently stir the sugar until it melts and stop stirring. Lower the heat to medium low.

2. While the sugar syrup is simmering, cube the unsalted butter into about +/-10 pieces.

3. Place egg yolks into a heatproof bowl (not plastic) and wait until the syrup reaches around 108C. Beat the egg yolks with a hand mixer at high speed

4. Cook the syrup until it reaches soft ball stage at 118C. (turn off the heat at 115C-116C and it will still rise)

5. Immediately pour the hot syrup into the egg yolks, beating it as you pour. (Use both hands efficiently)

6. Whisk the egg yolks until it is thick and pale, and forms ribbons as you lift up the beaters. If eggs are still warm, let it sit in a cool water bath.

7. Add in the butter (it should be 'dentable' and yet 'liftable' by now), gradually, beating well after each piece. Beat the buttercream until it is light and fluffy in texture. Add in vanilla extract.

8. Add in melted chocolate and mix well.

Notes from Wendy :

*If the buttercream turns soupy after the first few cubes of butter, stop adding butter and stop beating. Let the yolk sit in a cool water bath (water with a few ice cubes, not cold, but cool), scrape the base with a silicon spatula once every 10 seconds.. Check the yolks and feel with your fingers and see if it's still warm. Continue adding butter and beat.

Piping Gel:

75g castor sugar

60g water

1 tsp corn starch

2 tbsp lemon/lime juice

Method :

1. Mix corn flour and sugar.
2. Put all ingredients into a small pot.
3. Place pot over medium heat, stir constantly.(it will appear to be cloudy, don't worry.)
4. When mixture starts to boil, lower the heat.
5. Stir till mixture becomes thick.(it will be more translucent at this stage.)
6. Leave aside to cool and its ready to use.