Unsweetened chocolate is often labeled as 99% or 100% cacao, or bitter (as opposed to bittersweet) chocolate and it’s easy to find at any supermarket in America. In France, it’s called pâte de cacao. (In Paris, you can find it at
G. Detou, in bulk.) If it’s not possible to find it where you live, you could likely get away with just using 6 ounces (170 g) of the darkest bittersweet chocolate you can find.
For those new to making caramel, you can check out my post
How to Make the Perfect Caramel, as well as
10 Tips for Making Caramel, to help you out and to advise with any precautions.