Combine cake flour, powdered sugar, cocoa powder, and cold butter in a food processor and blend for 20 seconds.

Add egg yolks and blend until the dough lightly comes together. If the dough is too dry, add a small amount of milk or water.

Transfer the dough to a bowl and gently mix in chocolate chips and pearl sugar.

Place the dough on plastic wrap and shape it into a cylinder. Wrap tightly and chill in the freezer for 1 to 1.5 hours.

Cut the chilled dough into 1cm thick slices and roll each slice in granulated sugar.