Free concretes at Shake Shack

During DesignPhiladelphia, from Oct. 10-14, Shake Shack will host Shift Space Design and its installation of Fairmount Living Tiles, which allow anyone to create their own green roof or green space on a rooftop, deck or patio.

To celebrate this project, on Thursday, Oct. 11 from 5:30-7 p.m., Shake Shack (20th and Sansom Streets) will throw a "Concrete by Design Shake Shack Tasting."

The eatery will offer two comp frozen custard desserts, known as concretes. Both were created in collaboration with Philadelphia’s  Nook Bakery & Coffee Bar and La Colombe.

The Nook’s Fall Look has vanilla custard and a slice of graham cracker pumpkin pie from Nook Bakery. La Colombe’s Espresso Session is chocolate custard, La Colombe Nizza espresso beans, cannoli shells and cinnamon fudge sauce.