200g dark chocolate (70% cocoa solids), broken into small pieces
Line a large baking tray with cling film.
To make the salted caramel sauce, place the caster sugar in a dry, heavy-based saucepan and dissolve over a low heat, shaking the pan regularly.
Once the sugar has dissolved and is pale golden in colour, remove the pan from the heat and stir in the butter and cream. Season with salt to taste. Set aside to cool, then chill in the fridge for at least 30 minutes.
Place a heatproof bowl over a pan of gently simmering water, ensuring the bottom of the bowl doesn’t touch the water. Place the chocolate into the bowl and melt, stirring, until glossy and very smooth.
Pour the chocolate onto the lined baking tray. Use a butter knife to spread the melted chocolate out to a very thin layer using a butter knife and set aside to cool and set. Once the chocolate has set, break it into small shards.
Line a 900g loaf tin with cling film, leaving a wide overhang on all sides. Push the film right into the corners of the tin.
Fill the loaf tin about one-quarter of the way with ice cream, pressing it down into the corners and flattening the top.
Cover the ice cream with one-third of the chocolate pieces and top with one-third of the salted caramel sauce. Repeat the layering process two more times until the loaf tin is full, finishing with a layer of ice cream.
Cover with cling film and place in the freezer for at least six hours.
To serve, turn the parfait out of the mould and cut it into thick slices using a knife dipped in hot water.