I almost always use salted butter for shortbread because it’s what gives it that distinct taste.
If making the graham cracker crumbs yourself instead of purchasing them, you’ll need about 7 or 8 graham crackers.
You can make a half batch in an 8x8-inch baking dish. It will only need to bake for 25 to 30 minutes.
Dehydrated marshmallow bits are found in the grocery store near the hot chocolate, not near the other marshmallows.