Shift cake flour and cocoa powder into a bowl. Place aside.
Add the butter and granulated sugar in another mixing bowl. Beat with a hand mixer until light and fluffy.
Add whole egg liquid in batches and beat each time until mix well. (Leave egg liquid 10 g for brush dough log)
Add almond flour and beat until combined.
Add the cake flour mixture in the bowl and stir with a spatula until the mixture forms a dough. (Do not over stir)
Roll the dough into a long log and wrap with cling wrap. Refrigerate it for 2~3 hours to firm up the dough.
Preheat the oven 340°F/170°C.
Pour the brown sugar in the tray.
Brush the dough log with egg liquid lightly and roll it on the brown sugar.
Cut the dough log into 0.5 cm and line on a baking sheet.
Bake for 13~15 minutes in the preheated oven until golden. Remove from the oven and place to cool.
Serve the Chocolate Diamond Sablés. Finish and enjoy