Danny Meyer’s Shake Shack, a modernized version of the original roadside burger joint, has just opened a new outpost in the theater district at 44th St and 8th Ave and it’s huge and outrageous. They’ve got the same great burgers, dogs, fries, wine and beer, delectable shakes and have even added a few new twists on the heavenly frozen custard, concrete. Check out the Broadway themed “Jelly’s Last Donut,” which is vanilla custard with the famous Lower East Side’s Doughtnut Plant donuts, strawberry preserves and cinnamon-sugar. And if that isn’t music to your ears, try the already popular “Great White Way,” which is also vanilla custard, marshmallow sauce and “crispy crunchies.” One has to wonder how we survived before Shake Shack. Mamma Mia. Run, don’t walk. www.shakeshack.com