Salted caramel chocolate torte

Ingredients

175g digestive biscuits
85g butter

, melted
397g can caramel

(we used Carnation caramel)
1 tsp sea salt, plus extra to serve
300g plain chocolate (70% solids), broken into chunks
600ml tub double cream
25g icing sugar
2 tsp vanilla extract
salted caramel
chocolates, to decorate (find them in Waitrose, Sainsbury’s or Marks & Spencer)
single cream, to serve (optional