In a bowl, whisk together the cake flour, bread flour, baking soda, baking powder and coarse sea salt. Set aside.
2 cups minus 2 Tbsp (8.5 oz) cake flour, 1 2/3 cups (8.5 oz) bread flour, 1 1/4 tsp baking soda , 1 1/2 tsp baking powder, 1 tsp coarse salt
In the bowl of a stand mixer, combine the softened butter, brown sugar and granulated sugar. Cream together for a full 5 minutes, stopping halfway through to scrape the sides of the bowl.
1 1/4 cup (278g) salted butter, softened, 1 1/4 cups (10 oz) light brown sugar, 1 cup plus 2 Tbsp (8 oz) granulated sugar
Slow the mixer down to the lowest setting and add the eggs in one at a time mixing until completely combined.
2 large eggs
Add in the vanilla and mix.
2 tsp natural vanilla extract
Slowly add in the dry ingredients, mixing until just combined.
Pour in the bittersweet chocolate chips and mix until evenly distributed.
1 1/4 lbs Ghirardelli bittersweet chocolate chips, 60% cacao powder
Portion out the dough into 3.25 oz balls (I overfilled my #24 scoop).
Chop 2 oz of the chocolate bar and press some of the chopped chocolate onto the tops of the cookie dough balls, if desired.
8 oz Ghirardelli bittersweet (60% cacao) chocolate bars, divided
Sprinkle a little flakey sea salt on top of the cookie dough balls.
flakey sea salt
Place the cookie dough balls into a zip top bag and store in the fridge for 24-72 hours.
When ready to bake, preheat the oven to 350° F (180° C) and bake the cold cookie dough balls for 18-20 minutes or until the edges of the cookies are golden brown.
Allow the cookies to cool on the pan for 15 minutes and then transfer to a wire cooling rack to finish cooling completely.
Once completely cool, chop the remaining chocolate bars and melt in the microwave at 50% power for 30 seconds at a time until mostly melted. Use the residual heat to melt any remaining chocolate pieces while stirring until completely melted.
Spread approx 1-2 tbsp of chocolate onto the bottom of each cookies, setting the cookies onto a silicone baking mat, chocolate coated side down, allowing them to completely set up there.
Store in an airtight container for up to 3 days.