INGREDIENTS
4 tbsp
unsalted butter, softened
1/4 cup
+ 2 tablespoons light brown sugar (packed)
1
large egg yolk
1/2 tsp
vanilla extract
3 tbsp
unsweetened cocoa powder
1/2 cup
all-purpose flour
1/4 tsp
instant espresso powder
1/4 tsp
baking soda
1/4 tsp
salt
1/4 cup
(heaping) chocolate chunks
1 pinch
large-grained salt for sprinkling (optional)