Sift together the cake flour, bread flour, baking soda, baking powder, and salt into a medium sized bowl and set aside.  Can you just use all-purpose flour you ask?  You could, but the outcome just won’t be the same.  Here’s some substitute options for you: to make two cups of cake flour, combine 1 3/4 cups all-purpose flour with 1/4 cup cornstarch. To make one cup of bread flower, add one teaspoon of vital wheat gluten to a cup of  all-purpose flour.

A mixer is definitely recommended for this step unless you are looking for a good upper body workout.  Cream together the butter and sugars until light and fluffy, about 3-5 minutes.

Add in the eggs, one at a time, until combined, scraping down the bowl as needed.

Add in the vanilla and mix.

Gradually add in the dry ingredients, until just moistened.

Fold in your chocolate until evenly added throughout the dough.

You are now going to refrigerate your dough for at least 24 hrs.  Truth is the longer the better, but don’t leave them more than 72 hrs. Press plastic wrap against the dough, making sure it is completely covered. This is an important step, be patient, it’s worth it…

Take your dough out and let it come to room temperature.  Usually an hour or two on the counter will do the trick.

Preheat oven to 350°F.

Line and/or grease your baking sheets. Parchment is my best friend in this case.

Scoop your dough out onto the sheets. You can make them as big or as small as you like.  Don’t press the dough ball down!

Sprinkle the cookies lightly with a bit of fleur de sel or sea salt.

Bake 10-12 minutes for smaller cookies (mine took about 13 minutes), or 18-20 minutes for larger cookies.  Be careful not to over cook.

Allow the cookies to cool slightly on your baking sheet, then move them to a cooling rack to cool completely.

Enjoy with a glass of milk, a cup of coffee or tea!