Familiar flavor combinations like toasted coconut and caramel sea salt, chocolate peanut butter swirl, dark chocolate salted brownie and mint cookie are now in milkshake form.

With Frosty Swirls, customers will be able to add — or shall we say swirl — a tasty sauce into a Classic Chocolate or Vanilla Frosty. Frosty Fusions will blend a customer’s choice of sauce with ...