A few hours prior to making the cookie dough you will want to brown half of the butter. Add ½ cup/113g to a stainless or light colored saucepan over medium heat. Do not walk away while you do this, butter goes from browned to burnt very quickly. Allow the butter to melt. After melting the butter will foam and then bubble loudly. When it has turned a amber color and has a nutty fragrance it is ready. Remove from heat immediately and pour into a glass bowl, making sure to scrape the toasted milk fats into the bowl as well. After the butter is finished browning, pour into a small bowl and allow to come to room temperature. It does not have to completely re-solidify but I find the texture of the cookies better if it does. In a medium size bowl, weigh out and combine AP flour, bread flour, cinnamon, salt, and baking soda. Stir and set aside.
In the bowl of your stand mixer with the paddle attached, or a bowl that can be used with a hand mixer, combine unsalted butter, browned butter, brown sugar and granulated sugar. Mix together, creaming until butter is light and fluffy (2-4 min).
Add in eggs, one at a time, mixing in completely before adding the next.
Stir in vanilla.
Add in flour mix to the wet ingredients. Mix until just combined, not overmixing.
Add in chocolate chips and chopped chocolate bar, stirring in with a spatula by hand.
The dough should chill for at least 8 hours, but up to 48. You can either scoop cookie dough before chilling (I find this the easiest, I have a pan linked in the blog post above that is perfect for storing the scooped dough) and chill on cookie sheet covered or chill bowl of dough covered. If chilling whole bowl, cookie dough will need to warm up a bit before being able to scoop.
After cookie dough has chilled, cookie dough can be baked directly from the refrigerator. Bake at 350°F for about 11-12 minutes on a parchment lined cookie sheet on the center rack.
Remove from cookie sheet immediately after baking to cooling rack. Sprinkle with flaky sea salt while hot. Store in an airtight container. Enjoy!
