Blue Pea Flower Chocolate Cake Roll (Blue Sky White Cloud)

Ingredient

Method

4B grade egg yolks 20g caster sugar　　 100g LP flour 80g milk 60g veg oil 1/2tsp blue pea flower powder 2 drop blue coloring 4B grade egg whites 70g caster sugar (I use 50g since the buttercream is sweet enough, may adjust to your own taste) Filling: 100g dark chocolate coin, 35g milk 1tsp vanilla essence 50g homemade sour cream

1. Whisk egg white until bubble stage, gradually add sugar and whisk until soft peak form. Set aside. (if you may take longer time to prepare yolk mixture, may do this step after yolk mixture is done or temporary chill the meringue until ready to use.)  2. In another mixing bowl, beat egg yolks and sugar until light. 3. Add veg oil and beat until combined.  4. With the mixer on low speed, add the dry ingredients in two- three additions alternating with the milk, beginning and ending with the dry ingredients, and mixing each addition just until incorporated. 5. Take 1.5 tablespoons of egg white and egg yolk paste and mix well, then put the batter in the piping bag, draw the cloud pattern on the oil paper, bake in the oven for 2 minutes, and take out. 6. Add the blue pea powder and blue coloring into egg yolk mixture and mix well. 7. Next, add 1/3 of first portion of meringue into blue yolk mixture and mix to lighten the batter. 8. Pour the yolk mixture into the rest of meringue and fold gently until well combined. 9. Pour the batter into 12*14" prepared tin and tap the air bubble. 10. Bake at 170C for 15-20 minutes or until golden brown. 11. Remove from oven and immediately loosen cake from sides of pan and turn upside down onto kitchen towel generously sprinkled with powdered sugar (optional, and the purpose is to prevent the cake stick on the towel). Carefully remove paper.  12. While cake is hot, carefully roll cake and towel from narrow end. Cool on cooling rack at least 30 minutes. 13. Filling: Microwave the dark chocolate coins and milk few minutes until melted. While still hot add the vanilla essence and stir well. Once cooled, add the homemade sour cream and mix until combined. 13. Unroll cake and remove towel. Spread the filling and roll up the cake. Chill for 1 hour and trim off stiff edges of cake if necessary before served.