*peeks*
I noticed you used light brown sugar. Hmmm which kind of light
brown sugar did you use?
The recipe calls for "dark brown sugar, firmly packed", means the
kind that's daaaaaaark brown with molasses in it, and when you
measure it, you really have to press it down hard, like you're
trying to fit a large amount of sugar into a small cup.
The only time my cookies turned out too soft was when I reduced the
granulated sugar by half (hahahahaha).
Sugar plays a part in how crispy your cookies will turn out...