Thoroughly whisk together (or sift) the cake flour, bread flour, baking powder, baking soda, and salt. Set aside.
Using a mixer with the paddle attachment, beat the butter, brown sugar, and sugar until light and fluffy (about 5 minutes). Add the eggs, one at a time, mixing well after each addition. Mix in the vanilla.
Reduce mixer speed to low. Add the flour mixture, mixing just until combined (about 10 seconds). Stir in the chocolate discs, trying not to break them.
Cover the dough with plastic wrap, pressing the plastic directly against the dough. Chill for 24 to 72 hours.
Preheat oven to (175°C). Line baking sheets with parchment paper.
Divide the dough into (99g) portions. (Use a #14 or #16 scoop to get about ¼ cup of dough and use your scale to adjust.) Place the mounds of dough on the prepared pans. Sprinkle the top of each cookie with a pinch of sea salt.
Bake 18 to 20 minutes, or until golden brown but still soft.
Cool on the pans on a wire rack for 10 minutes. Then transfer the cookies to a rack to cool completely.
