the butter in a 2-quart saucepan
over low heat. Set aside to cool slightly.
together the flour, salt and baking soda
onto a paper plate. Pour the butter into your stand mixer
's work bowl. Add the sugar and brown sugar and beat with the paddle attachment on medium speed for 2 minutes.
together the whole egg
, the egg yolk, milk and vanilla extract in a measuring cup. Reduce the mixer speed and slowly add the egg mixture. Mix until thoroughly combined, about 30 seconds.
Using the paper plate as a slide, gradually integrate the dry ingredients, stopping a couple of times to scrape down the sides of the bowl. Once the flour is worked in, drop the speed to "stir" and add the chocolate chips
. Chill the dough for 1 hour.
Preheat the oven to 375 degrees F and place racks in the top third and bottom third of the oven.
Scoop the dough
into 1 1/2-ounce portions onto parchment-lined half sheet pans, 6 cookies per sheet. Bake 2 sheets at a time for 15 minutes, rotating the pans halfway through. Remove from the oven, slide the parchment with the cookies
onto a cooling rack
and wait at least 5 minutes before devouring.