INGREDIENTS
1 1/2 cups
all-purpose flour
1 1/2 cups
bread flour
1/4 tsp
baking soda
1 tsp
baking powder
1 tsp
fine sea salt
2 sticks
unsalted butter, divided
1/2 cup
granulated sugar
1 1/2 cups
packed dark brown sugar
2 tsp
vanilla
2
large eggs, plus 1 egg yolk at room temperature
1 lb
chocolate, chopped into chunks
Fleur de sel (or other finishing sea salt), for sprinkling