Me, too. My sister-in-law does something to it that makes them come out extra thin and crispy - not like a regular Chips Ahoy, more like wafers.
Yes, under-baking is a good way to avoid crisp cookies. I bet replacing some of the sugar with corn syrup would work even better if you want to make sure you don’t get any crispness.
When we were kids, my sister once ran out of flour when making chocolate chip cookies, and replaced the missing flour with powdered sugar. (Hey, it looked the same.) She made lace cookies – they were very thin, with holes, and sweet and crisp. I bet your SIL adds extra sugar, or leaves out some flour, or some of both.
I tried baking some cookies and under cooking them a little and they were soft in the center but the edges and bottom of the cookie were still crunchy. I want to make them so they’re not crunchy at all anywhere.
If you want zero crunch, you’re going to have to start getting out there with techniques, ingredients, or equipment. Lacking the extruded, chemical goo that you get from things like the Chip Ahoy, you’ll probably have to go with technique.
So the two I’ve heard of, but haven’t experimented with, is either one of the various ‘no-bake’ options, or a steam oven. The no-bake options normally cut out eggs for food safety, and I tend to consider them more . . . cookie-like power bars? They aren’t bad, but not my cup of tea. Here’s a representative recipe
Alternately, I have heard very good things about steam/convection oven combinations that can cook food quickly without drying it out, which should also prevent the crisping you’re worrying about. Again, a representative device (that I have not used)
The only other thing I can suggest if you want to avoid the crunch bottoms (and don’t want to invest $$$ in steam or eat unauthentic cookies) is to bake on a less conductive surface - dark metal baking sheets are right out then. I have heard inconsistent information on silicone baking sheets, some say they get softer bottoms due to insulation, but others say they overcrisp as the non-stick allows extra spreading.
Perhaps try a ceramic baking sheet, or, if you have a pizza stone (I do and love it), try baking a few experimental cookies straight on the stone - the lower conductivity should help, but you’ll definitely still want to use high-moisture recipes and underbake.
Best of luck!
A friend makes them…so good…I have never baked them myself, but this is the recipe she gave me:
The Best Soft Chocolate Chip Cookies | Sally’s Baking Addiction (sallysbakingaddiction.com)
I’ve been watching this thread for tips on what to avoid (i love a crisp cookie, and don’t find soft commercial cookies like “chips ahoy” very appealing even if I’m quite hungry) and I have to say, “thanks for that link”. The author gives good pointers on the science of what produces different outcomes in cookies.
I’m sure it’s also helpful for people who prefer soft cookies.
I think you might like to read this:
The Food Lab’s Chocolate Chip Cookies Recipe (seriouseats.com)
This is where i miss the “like” button. Thanks.