Preheat the oven to 110 C / Gas mark ¼. Line baking trays with foil or baking parchment.
In a large, clean glass or metal bowl, whip egg whites, vinegar and salt until soft peaks form. Gradually add sugar while continuing to whip until stiff peaks form, about 5 minutes. Fold in 1/3 of the crushed candy canes, reserving the rest. Drop by heaped teaspoonfuls (5cm apart) onto the lined baking trays. Sprinkle remaining crushed candy canes over the top.
Bake for 90 minutes in the preheated oven, or until dry. Cool on baking trays.