Brown the butter then pour into a heatproof bowl. Mix in the cold butter until completely dissolved in the brown butter.
Brown Butter
Add in the brown sugar, granulated sugar, and vanilla extract. Mix until fully combined.
Add Sugars
Step 2
Add in egg and egg yolk until combined for about 30 seconds.
Add the eggs
Step 3
At this point, you will have a pretty dark brown color, mix for another minute and a half to two minutes until you achieve a much lighter color.
Keep Mixing
Step 4
Mix in the whisked together dry ingredients and mix in until just combined.
Combine
Step 5
Add chocolate chips. While oven preheats let the dough sit for at least 10 minutes.
Add Chocolate Chips
Step 6
Marinating the dough this gives the flour time to rehydrate and the cookie dough to meld more together.
Marinate the Cookie Dough
Step 7
When ready use a medium cookie scoop to portion the cookie dough. Bake for 9-12 minutes or until golden brown but still look a bit undercooked, sprinkle with fleur de sel at this point, if desired.