Milk Bar and Shake Shack have collaborated on two limited-edition shakes. The Cornflake Chocolate Drizzle Shake and Chocolate Birthday Cake Shake. The former is a hand-spun mix of milk bar crumbs and milk bar frosting. The milk bar’s Vanilla frozen custard is mixed with Milk Bar Cornflake Crunch and topped with Milk Bar chocolate drizzle and mini marshmallows. You can simply visit Shake Shack’s Instagram Stories to use the B’Day Randomizer to select random dates. You will receive a code to redeem a $5.99 USD discount for a Shake Shack milkshake. If you’re a Shake Shack user, you can get early access to these offerings.