In a large bowl, whisk together the sugars, salt, and butter until a paste forms with no lumps.
2
Whisk in the egg and vanilla, beating until light ribbons fall off the whisk and remain for a short while before falling back into the mixture.
3
Sift in the flour and baking soda, then fold the mixture with a spatula.
4
Fold in the chocolate chunks, then chill the dough for at least 30 minutes. For a more intense toffee-like flavor and deeper color, chill the dough overnight. The longer the dough rests, the more complex its flavor will be.
5
Preheat oven to 350°F (180°C). Line a baking sheet with parchment paper.
6
Scoop the dough with an ice-cream scoop onto a parchment paper-lined baking sheet, leaving at least 4 inches (10 cof space between cookies and 2 inches (5 cof space from the edges of the pan so that the cookies can spread evenly.
7
Bake for 12-15 minutes, or until the edges have started to barely brown.