I followed this recipe fairly strictly, except I used 1/2 cup butter (1 stick) rather than 2 sticks. I ran out of brown sugar so I used about 1/2 cup brown sugar , 1/2 cup regular white sugar, and it seemed to be no different. Go sparingly on the chocolate chips---I "eyeballed" it and ended up making the popcorn a little bit too chocolatey, and overcoming some of the caramel taste. Also, my popcorn started to burn after 45 minutes, so I didn't bake it the full hour.