Add 2 cups of spiced apple cider to a saucepan and turn the heat to high. Boil until it has reduced to about 1/2 cup of liquid, stirring occasionally. In a large saucepan, this took almost exactly 15 minutes. In a small saucepan, it took more like a half hour.
Transfer to a container and chill completely. You can freeze for one hour, or stick it in the fridge for 2-3 hours.
Add 2 cups of vanilla ice cream to a blender. Add the reduced cider. Add 2 tablespoons caramel sauce. Blend until smooth. Add more regular apple cider if it is too thick, or more ice cream if it's too thin.
Serve with additional caramel drizzled on top.
Notes
The deliciousness of this shake depends a great deal on the quality of the ingredients. I mean, there are only 3. Buy the good stuff.Source: The Food Charlatan