01 - Combine sugar and water in a small saucepan over medium heat without stirring until the mixture reaches a deep amber color, about 5 to 7 minutes.
02 - Remove from heat, whisk in butter gradually, then slowly add heavy cream and sea salt, stirring until the sauce is smooth; allow to cool to room temperature.
03 - Place milk, cooled caramel sauce, ice cubes, and vanilla extract into a blender and blend until frothy and smooth.
04 - Divide the caramel frost between two glasses, topping each with whipped cream, a drizzle of caramel sauce, and a sprinkle of cinnamon if desired. Serve immediately with a straw.