Directions

1. Line the base of a deep, round 20cm loose-bottomed cake tin with a circle of baking parchment. Line the sides with one long strip that comes just above the sides of the tin - staple or paper clip where the strip overlaps to hold it in place.
2. Crush the biscuits in a plastic bag or bowl with the end of a rolling pin. Stir into the melted butter, then evenly press into the bottom of the tin. Chill for 10 mins.
3. Reserve 2 tbsp of the caramel. Stir the sea salt into the remainder and spoon into the centre of the biscuit base. Gently spread so the base is evenly covered but a visible 1-2cm border of biscuit remains around the edge. Chill for 20 mins while you make the chocolate layer.
4. Gently melt the chocolate in a large heatproof bowl over a pan of barely simmering water. Stir 1 tbsp of the cream into the reserved caramel, then cover and chill until ready to decorate. Once the chocolate has melted, turn off the heat but leave the bowl where it is, and gradually stir in the remaining cream until you have a smooth, shiny, thick chocolate sauce. Sift in the icing sugar and stir in with the vanilla extract. Lift off the heat and let the mixture cool for 10 mins.
5. Ladle or pour the chocolate mixture around the edge of the torte first, so it fills the biscuit border, sealing the caramel in the centre. Then ladle or pour in the rest and gently shake to smooth the surface. Chill for at least 5 hrs or up to 24 hours until firm.
6. Remove the torte from the tin, then carefully peel off the strip of paper and transfer to a serving plate. Dot the chocolates on top. Spoon the reserved caramel-cream mixture into a small food or freezer bag. Snip off the tiniest tip of the corner to make a very small opening, then squiggle lines of caramel over the top. Chill until ready to serve. Scatter with a pinch or two of sea salt before serving, then thinly slice. Eat with a drizzle of single cream, if you like.