Combine cake flour, almond flour, baekryuncho powder, powdered sugar, and salt in a food processor. Pulse for 10–15 seconds until well mixed.

Add cold butter cut into small pieces. Pulse repeatedly until the butter is fully incorporated and no visible chunks remain.

Add egg yolk and pulse until the dough forms a cohesive ball. Mix in chunk chocolate until evenly distributed.

Shape the dough into a long cylindrical log. Adjust the size based on preference.

Chill the dough in the freezer for 20 minutes. Slice into 0.7–1cm thick rounds.