Why does everyone chill their cookie dough for exactly 30 minutes
Every recipe I see online says to chill cookie dough for 30 minutes in the fridge, and I think that number is mostly made up. The butter in a standard batch needs at least 2 hours to firm up enough to stop the cookies from spreading thin, and I found that out the hard way with a batch that turned into one big sheet pan cookie at my sister's place in Denver last month. The 30 minute thing seems to be more about fitting it into a blog post than about actual dough chemistry. Has anyone tested longer chill times and noticed a real difference in the bake?