The first time my SC has gone wrong! I buy flour in bulk bags, then measure out double batch amounts into ziploc bags and into freezer. This time I thought I'd be smart and go ahead and add the salt and baking powder, so it's all ready to go at cookie-baking time. First few batches I did with that mixture over the weekend were fine (I had put them in the freezer friday evening, then baked on Sunday) Now, I have last-minute cookies, so I throw them together, bake.....flat cookies! And look done on the outside, but not done enough. I tried one, they are chewy, so I put back into oven, but still flat.
Any ideas??

My only thought is maybe the baking powder reacted with the moisture in the freezer. That would explain why it didn't react when you made the cookies. Maybe in the future premix the flour and salt, but leave out the baking powder. I'm sorry this happened to you ((hugs))

you know, while these were baking, I did put the dough in double ziploc bag and into freezer, beause I only needed 16 cookies, but now I'm wondering if it's just a big flop, along with the other six bags of flour mixture I have left in the freezer. Now, mind you, I didn't let it come to room tempeature, I was in huge hurry just to get them baked. Could that be the problem?

Weird! I froze the leftover dough from the flopped cookies for week or so, took out of freezer and into refrig overnight, was fine. Today I've done two batches of the flour/baking powder mixture from the freezer, brought it to room temp, working fine. Dunno what the problem was, maybe it was just still too cold when I mixed it. Maybe it was some weird cookie black cloud over me. But, they tasted fine, they were the cheerleader bouquet in my photos.
Thanks for all y'all's tips !