unsalted butter • (2.5 oz, 7.8 Tbsp) bread flour • (2.5 oz, 7.8 Tbsp) cake flour • salt • cocoa powder, sugar-free • powdered sugar • cold water • ※70g bread flour and 70g cake flour can be replaced with 140g all-purpose flour • egg yolks, around 60g (2.1 oz) • granulated sugar • cake flour, or all-purpose flour • vanilla oil, optional •