Tired of the same old pumpkin pie? Even if you’re not, Shake Shack is out with a new twist on the seasonal dessert fave. The Pumpkin Pie, Oh My! concrete blends a slice of pie with vanilla frozen custard, and is available now at the Rittenhouse burger joint for $4.25 per half or $6.50 for the full monty. If you’re thinking the combo sounds amazing, you’re not alone: it’s the Shack’s most popular concrete ever. Snag a cup (or two, or three) before December 2, when the flavor disappears, not to resurface until Thanksgiving 2013.