Salted Chocolate Chunk Shortbread Cookies (las favoritas de Noah)

Description

Line two rimmed baking sheets with parchment paper.
Using a stand mixer fitted with the paddle attachment, beat the butter, both sugars and vanilla on medium-high speed until it’s light and fluffy (3-5 mins.)
Using a spatula, scrape down the sides of the bowl and, with the mixer on low, slowly add the flour, followed by the chocolate chunks, and mix just to blend. Do not overmix.
1. If necessary, knead the dough with your hands to make sure the flour is incorporated. At this point, the dough should be smooth and fell like Play-Doh with no pockets of flour.
Divide the dough in half, placing each half on a large piece of plastic wrap. Fold the plastic wrap over so that it covers the dough to protect your hands from getting all sticky. Using your hands, form the dough into a log shape.
Each half should form a 6″ log, 2 to 2 1/4″ in diameter.
Chill until totally firm, about 2 hours.
Heat the oven to 350F.
Brush the outside of the logs with the beaten egg and roll them in the demerara sugar.
Using a sharp knife, carefully slice each log into 1/2″ thick rounds. If the cookies break or fall apart, just press them back together – the dough is very forgiving.
Place the cookies on the prepared baking sheets about 1″ apart (they won’d spread much).
Sprinkle with flaky salt.
Bake until the edges are just beginning to brown, 12-15 minutes.
Let cool slightly before eating them all!