Caramelising white chocolate is not a commonly used technique, but is well worth it if you are passionate about baking and chocolate work. The process of caramelisation turns the sugar into caramel, creating a rich toffee akin to dulce de leche, but with cocoa undertones thanks to the presence of cocoa butter.
To caramelise white chocolate, use a good quality bar with a high cocoa butter content (about 30% - ideally 32%), as this helps the chocolate to melt and break down evenly. A chocolate of 20% or lower will not melt as evenly, and may dry out.