Line a baking tray with baking paper (alternatively cover with cling film).
Chop the chocolate and melt gently over a bain-marie.
In the meantime, for the topping, chop the caramels into small pieces with a sharp knife and store temporarily in the refrigerator until further use. Chop the salted pretzel to taste.
Pour the liquid chocolate onto the prepared tray and spread it about 5 mm thick. Top with salted pretzels, caramel pieces and Smarties. Finally, sprinkle some salt flakes on top.
Place the tray in a cool place (e.g. refrigerator) for several hours and allow the chocolate to harden completely.
Break or cut the finished chocolate into coarse pieces.