Bake on a greased cookie sheet at 350° for 8-9 minutes. They will look like they should cook a little longer. Resist. They'll finish setting up on the cooling rack and be chewy and wonderous! Like thin little fudge brownies.
Remove from the oven and allow to set on cooling rack for 2-3 minutes.
After that, transfer the cookies from the cookie sheet and allow to finish cooling on the rack.