Place the condensed milk, double cream and 100ml of the caramel in a bowl. Using a hand held electric whisk or stand mixer, whisk the ingredients until the whisk begins to leave trails in the mixture, and when you lift the whisk a ribbon of cream falls back into the bowl.
Pour into a suitable container (a 2lb loaf pan or a Tupperware work well).
Warm the remaining caramel on the defrost setting of your microwave for a few seconds to loosen it then swirl through the ice cream.
Freeze for at least six hours.
Serve and enjoy.
* I use Carnation caramel but any caramel sauce or dulce do leche will be fine.