Just Add Water
One small fix was to swap out the regular chocolate chips for mini morsels. The mini chips were easier to bite through; in fact, I enjoyed their delicate crunch so much that I pressed more into the ice cream around the rim of the sandwich for a dose of Chipwich nostalgia.
But then I made a fortuitous discovery. Until now, I’d been freezing the sandwiches for just a few hours. When I happened to leave a batch in the freezer for nearly 24 hours, I noticed that the cookies were much softer than before, clearly having absorbed more moisture from the ice cream over time. It made me wonder if I should be making a moister cookie from the start.
To find out, I went straight to the source, adding various amounts of water to the dough along with the egg and vanilla. Ultimately, I settled on 2 tablespoons, which, combined with a good 8 hours in the freezer, made for cookies sturdy enough to sandwich the ice cream but tender enough to bite through with just a hint of snap. (For a full explanation, see “How More Water Makes Softer Frozen Cookies.”)