Simply put, you won't be disappointed, and I consider myself a connoisseur of things that will surely make you obese if you try hard enough.
We've been here twice now, generally I'd try a place more times than that before giving a precious 5-star Yelp review, but I'm confidently in love.
Tips:
1. Get the brownie as at least one of your sandwich sides
2. Don't get it heated (it makes the cookie hard and doesn't really add much IMHO)
3. The ice cream in general is phenomenal, cookie dough is my favorite but I think I'll be trying Rocky Road next time
4. If you're willing to share, they're splittable, just ask for it to be cut in half. All the joy, only half the guilt.
Enjoy it!