I couldn’t spot the grammar error. I was primed to read the sentence for errors so I didn’t look at the meaning much. But I also didn’t think the instructions were giving “stir” as a step. I read it as saying “peel back so that you have the option to stir”.
I tend to try and fill in the blanks as to what I think things should mean if something looks weird to me. That contributes to my challenges in trying to read stuff literally.