If you make dipped apples, remove the stems of the cleaned apples, then set them on a parchment-lined baking sheet a few inches apart. Insert a skewer about three-quarters of the way through each apple. If you want apple slices, clean the apples but wait to cut them into slices until right before serving.
Put the cream in a small heavy pot. Cut the vanilla bean in half lengthwise, and using the tip of the knife, scrape the seeds of the vanilla bean into the cream. Add the vanilla bean to the cream as well. Simmer the cream at a very low temperature for 10 minutes. Do not let the mixture boil.
Remove from the heat and pour the mixture through a very fine-mesh sieve into a bowl to remove the vanilla bean and any loose fibers.
Place the vanilla cream back into the pot, then add the sugar, corn syrup, and butter making sure that the mixture doesn't splash up onto the sides of the pot. Place the pot over very low heat and stir gently until the sugar is dissolved, increase the heat to medium-high heat and clip a candy thermometer onto the side of the pot. Heat the caramel mixture, without stirring, to 245 degrees F.
Meanwhile, put a few handfuls of ice into a large bowl, big enough to fit the pot you are cooking the caramel.
When the caramel mixture reaches 245 degrees F. (and stays there for at least 1 minute), remove from the heat and place the pot on top of the ice for 30 seconds to slow the cooking. Remove the pan from the ice.
If your caramel is cooked correctly and sets, tilt the pot toward you to create a big pool of caramel. Immediately begin dipping the apples into the caramel. Dip each apple only once, and don't worry about coating it evenly or completely.
Return the caramel-dipped apples to the baking sheet and refrigerate until the caramel is set, about 10 minutes.
If you don't want to dip apple slices instead just slice them into wedges and serve the warm caramel as a dipping sauce. Serve immediately. Enjoy.