Core Insights - Portillo's, a Chicago-based fast-casual restaurant, is launching a limited-edition Birthday Cake and Cake Shake, available until April 6, 2026, to celebrate its dessert lineup and the first anniversary of its loyalty program, Portillo's Perks [1][4]. Product Details - The new Birthday Cake features two layers of cake with Funfetti® rainbow sprinkles, topped with vanilla frosting and additional colorful sprinkles, similar to Portillo's famous Chocolate Cake [2][3]. - Customers can purchase the Birthday Cake by the slice, as a whole cake, or blended into a Cake Shake [3][4]. Promotional Offers - To celebrate the first birthday of Portillo's Perks, members can enjoy a slice of Birthday Cake for $1 with a minimum purchase of $5 from March 9-15, 2026 [5]. - New members of Portillo's Perks can sign up online to receive a free large French fry with their first order of $5 or more [6]. Availability - The Birthday Cake and Cake Shake will be available at all participating Portillo's locations nationwide starting March 3, 2026, while supplies last [7].