Peel your apples, and cut each apple into 3 equal segments, removing the stem and core. Place your peeled apple segments in a large container or bowl, and submerge them with hot water from your tap. Let your apples sit in the water for at least 10 minutes.
While your apples are soaking, make your caramel! Using a 9" round cast-iron pan, cover the bottom of your pan with an even layer of your granulated sugar, then drizzle your 1 tbsp vinegar and 1 tbsp water to cover the sugar. Turn your stove top to medium heat, and allow the sugar to come to a boil, before reducing into a caramel. Once you see a light brown colour, tilt your pan in a circular motion to make sure the sugar caramelizes evenly. Once your sugar is evenly caramelized, stop the caramelization by stirring in your cold butter. Continue stirring for 2-3 minutes, or until the caramel is thick and emulsified.
