This may or may not be a surprise to people, but with as much baking that I have done, I have never, ever, ever used parchment paper. I mean what's the point? I've been making great cookies for years, and only a few batches of cookies have given me some grief. A few appeared to spread a little more than they should have, a few didn't really seem to have an actual bottom, and one or two glued have glued themselves to my bake pan and I had to chisel them off, but I never thought parchment paper would fix that.
Then a friend of mine and I were chatting about baking and debating over cooking spray versus shortening, and parchment paper came up. Considering the past week I had had a few cookies that required a little elbow grease to get them off the pan, and considering she talked so highly about it, I said, ok, I'll give it a go.
Well I made some cookies yesterday and they stayed rounder and came off super easy. Why hadn't I thought about parchment sooner? I won't say its going to become a staple in my kitchen, but if you've continuously found your cookies spreading too much, and being big, flat pancakes, parchment paper, in addition to extra baking soda, might help you out.