In a large bowl, add the dry ingredients -all flour, cornstarch, baking soda, baking powder and salt. Set aside.
Place butter and sugars in the bowl of a stand mixer. Cream together using the paddle attachment, until light and fluffy. This should take at least 5 minutes. Make sure to scrape the sides of the bowl about half way through mixing so that everything mixes evenly.
Add in egg, egg yolk, and the vanilla bean paste. Mix again on medium speed for at least 2 minutes. Scrape the sides of the bowl again to make sure all of the ingredients are combined and there are no unmixed pockets of butter
Add the bowl of dry ingredients to the wet mixture in the standmixer. Mix again until dough forms. Add in the 1/2 cup of milk chocolate chips (save the other cup for later), the 1/2 cup of MINI semi-sweet chips, (save the other cup for later) and the chopped chocolate. Turn mixer on low and mix to combine
Place a clean sheet of parchment paper on a workspace
Using a VERY large cookie scoop or kitchen scale make dough balls about 6 oz each. This will yield 6 giant cookies. If you wish for them to be smaller, you can also make them about 4 oz but this will reduce the baking time.
In a small bowl add the extra chocolate chips - 1 cup of mini semi sweet, 1 cup of milk chocolate chips , and 1 cup of full sized semi sweet chips. Mix around so the chips are varying sizes throughout the bowl
Press each dough ball into the chips and coat each ball in the chip mixture. Make sure to press in a few if there are any areas without. Do not coat the bottom of the cookie- only the top and sides as the bottom would burn if covered in chocolate in the oven
Place dough balls on a parchment lined baking sheet and cover with cling wrap. Let dough rest for at least 24 hours (I know, it is a long time)
To bake, preheat the oven to 350 degrees F. Place two or three cookies on a baking sheet at least 5 inches apart and bake for 16-20 minutes. Cookies will be done when the edges slightly browned but the inside is still gooey and underdone
When you remove the cookies from the oven make sure to bang the cookie sheet on the counter a few times to help flatten out the cookies
Use a circle cookie cutter or rubber spatula to push in any wonky or crazy cookies edges back into a circle shape
Let cool and press any extra chocolate chips on time. Top with flakey salt and enjoy!
