Cake collars are thin, flexible strips made from materials like acetate or parchment paper, used to support the sides of cakes or desserts during assembly. They help create smooth, clean edges for layered or mousse cakes and prevent fillings or toppings from spilling over. Cake collars are often used for delicate or no-bake desserts, allowing easy removal once the dessert has set, maintaining the cake’s structure and appearance. They're a useful tool for bakers looking to achieve professional-looking results with minimal effort.