Lightly butter a lipped baking tray and spread the almonds over it in a thin, even layer. Put the sugar, butter, salt and 4 tbsp water into a smooth-bottomed frying pan and heat gently, stirring, until the sugar dissolves. Increase the heat and boil for about 5 mins, or until it starts to turn light golden brown. Stir every now and again as some patches will start to caramelise faster than others. Carefully tip the caramel over the nuts and leave to cool completely.
Once cold, shatter the caramel. An easy way to get clean sharp pieces is to put the point of a sharp knife vertically onto the caramel and bash the handle with a rolling pin, like a hammer and chisel. Serve on top of the Chocolate amaretti puddings. Keep for up to 2 days in an airtight container, interleaved with non-stick paper, in a cool, dry place (not the fridge).