1/3 cup salted butter
1/3 cup light brown sugar, packed
3 tbsp white sugar
2 tsp vanilla extract
1 large egg yolk
3/4 cup all purpose flour
1/2 tsp baking soda
1/3 cup chocolate chunks + 2-3 tbsp chocolate chips
Place the butter in a microwave safe bowl and melt partially in a microwave, just enough to be mixable. Whisk in the brown sugar, white sugar, vanilla into the bowl of butter. Stir until completely smooth and then add the egg yolk.
Add the flour and baking soda together in the bowl and stir well until dough pulls away from the sides of the bowl. Chop the chocolate and add to the dough, along with the chocolate chips.
Place the dough in the refrigerator for at least 1/2 hour to cool. Preheat oven to 325F when ready to bake.
Roll dough into 24 small balls, then place on ball on top of another and smooth out to make one larger ball, without flattening. This allows this cookie to be crispy on the outside and softer in the middle.
Bake for 9-12 minutes, until golden brown on top. Keep cookies on cookie sheet for 3 minutes before removing to a cooling rack.