Melt the butter until it starts to brown be careful not to burn the butter allow to cool
In a large bowl, whisk together the sugars, salt until a paste forms with no lumps.
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
Sift in the flour and baking soda, then fold the mixture with a spatula (Be careful not to overmix, which would cause the gluten in the flour to toughen resulting in cakier cookies).
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.
Preheat the oven to (180°C). Line a baking sheet with parchment paper.
Scoop the dough with a spoon onto a parchment paper-lined baking sheet, leaving space between cookies
Bake for 12-15 minutes, or until the edges have started to barely brown.