Excellent question, reader Josh! Toffee sauce is similar to caramel sauce in the sense that it’s made from sugar, butter and/or cream, the main difference is the degree to which it’s cooked. Toffee is only cooked to the point that the sugar in it melts, at which point it becomes usable. Caramel is cooked well beyond the melting stage, through all the various candy phases until the sugar molecules themselves start to break into pieces. It’s those pieces that give caramel its rich flavors and amber-brown color, since some of the chemical whatsits in the mix are actually pigments. Toffee sauce wouldn’t have much of a color (other than maybe very light brown) if it weren’t for the fact that it’s made with brown sugar, and brown sugar already has caramelized sugars (molasses) in it. Thanks, Josh!