beat yolks with 1 tbsp flour, set aside

beat egg whites with sugar to make hard foam

pour hard foam into yolk mixture and fold lightly and slowly to combine

add in flour bits by bits and fold lightly and slowly to combine

preheat oven to 300 F

grease and flour 6 8 inch round pans and pour about 1/3 cup + 1 tbsp of batter onto each pans, spread evenly. (if you don't have 6 pans, bake one layer at a time)

bake cake for 8-10 minutes

meanwhile, bring to boil water and sugar until sugar dissolved then add in butter, take off from heat, stir until butter dissolved; set aside to cool completely

sift cocoa powder and add into cooled butter mixture and whisk well

spread cream on 5 layers and stack them; leaving 1 layer on a parchment paper

melt sugar into caramel; work quickly, pour and spread caramel onto the last layer

brush a knife with oil, and slice caramel layer, please note although caramel hardens very quick, it can be still very hot underneath, so please don't burn yourself

transfer caramel layer on top of the 5th layer

cake is ready to be served