Start by making the caramel sauce. Unwrap the toffees and place into a saucepan with the cream and gently heat together until the toffee melts and you have a caramel sauce. Allow to cool. Meanwhile, heat a large pan with 1 tbsp oil and add in the popcorn kernels. Place on the lid, shake around and allow the kernels to pop. Remove off the heat and discard any corn which didn’t pop. Make a buttercream by beating together the butter, icing sugar and vanilla for 8-10 minutes until soft and fluffy. Place into a piping bag fitted with a start nozzle and pipe rosettes on top of the cupcakes. Mix half of the caramel sauce with the popcorn to coat and grind over some coarse sea salt. Take spoonful’s of the caramel popcorn onto the buttercream. To finish, drizzle over the remaining caramel sauce and serve.