The Strawberry Rhubarb Shake features strawberry and rhubarb mixed with vanilla frozen custard, topped with whipped cream and shortbread streusel, while the Chocolate Pudding Shake includes a blend of chocolate pudding and chocolate frozen custard, topped with whipped cream, fudge graham cookie crumbs, and cocoa nibs.
Prices vary but the new, seasonal shakes go for $5.99 in my area (versus $5.49 for Shake Shack's regular menu shakes).
Photo via Shake Shack.