In a large mixing bowl whisk together the flours, baking soda, baking powder and salt into a bowl. Set aside. 2 cups minus 2 tablespoons (8 1/2 ounces) cake flour 1 ⅔ cups (8 1/2 ounces) bread flour 1 ¼ teaspoons baking soda 1 ½ teaspoons baking powder 1 ½ teaspoons coarse salt
Using a mixer fitted with paddle attachment, cream butter and sugars together until very light, about 5 minutes. 2 ½ sticks (1 1/4 cups) unsalted butter 1 ¼ cups (10 ounces) light brown sugar 1 cup plus 2 tablespoons (8 ounces) granulated sugar
Add eggs, one at a time, mixing well after each addition. Stir in the vanilla. 2 large eggs 2 teaspoons pure vanilla extract
Reduce speed to low, add dry ingredients and mix until just combined, 5 to 10 seconds. Add the chopped chocolate and mix on low speed to incorporated. You can scoop the cookie dough at this point into balls or chill the cookie dough in the bowl. Press plastic wrap against dough and refrigerate for 24 hours, up to 72 hours. 1 ¼ pounds chopped chocolate
When ready to bake, preheat oven to 350℉ (180℃). Line a baking sheet with parchment paper or a nonstick baking mat. Set aside.
Scoop six 3 1/2-ounce mounds of dough (the size of generous golf balls) onto baking sheet. I only bake 6 on a cookie sheet at a time because of their size. These are large cookies! You can scoop smaller cookies but adjust the baking time.
Bake until golden brown but still soft, 18 to 20 minutes. Cool on the baking sheet for 5 minutes, then transfer to a wire rack.
Once cookies are cooled, melt the chocolate in a bowl. Then dip the bottom of each cookie in the melted chocolate or spread the chocolate on with an offset spatula. Place the cookies back onto the parchment paper chocolate side down and let cool until harden. 8 ounces semi-sweet chocolate