Line a 20cm brownie tin with baking parchment
Mix the crushed biscuits with the melted butter, then press it firmly into your tin and refrigerate for 20 minutes.
Sugar will form clumps and eventually melt into a thick brown, amber-coloured liquid as you continue to stir. Be careful not to burn.
Once sugar is completely melted, immediately add the butter. Be careful in this step because the caramel will bubble rapidly when the butter is added.
Stir the butter into the caramel until it is completely melted, about 2-3 minutes. A whisk helps if you find the butter is separating from the sugar.
Very slowly, drizzle in the cream while stirring.
Allow the mixture to boil until it reaches a temperature of 112 – 115c. Anything over the 115c will almost certainly give your a lovely hard toffee and a dentist bill..
Remove from heat and stir in 1 teaspoon of salt. Allow to cool down before pouring over the crushed biscuit base.
200g dark chocolate
Melt the chocolate in a bowl, over a pan of water.. Pour the dark chocolate over the caramel.