Preheat the oven to 170 degrees or gas mark 3.
Line a square 20 x 20 cm tin with baking paper and grease well.
Over a pan of hot water, melt the chocolate and butter in a bowl.
Add the melted butter and chocolate to the caster sugar, plain flour and eggs and mix well.
Pour the mixture into the tin and add the popcorn. I just placed pieces randomly into the brownie (you need to push these down to stop them popping out the top!)
Bake for 30-35 minutes until it begins to flake on top. Be careful not to overcook as this can affect the gooey centre.
While the brownie cools, heat up the caramel sauce in a saucepan and add the salt. Once it has a smooth, pourable consistency, drizzle across the brownie and enjoy.