Line the base and sides of a 23cm non-stick springform pan with baking paper

To make the raspberry ripple, place half the raspberries and sugar in a medium non-stick frying pan

Heat, stirring and mashing the raspberries with a wooden spoon, over medium heat until the mixture is smooth and comes to the boil

Pass mixture through a sieve to remove seeds. Cool to room temperature

Spoon ice-cream into a large bowl. Set aside to just soften. Stir in custard and peppermint crisps until well combined

Fold through the remaining frozen raspberries. Gently swirl (don't over mix) the cooled raspberry ripple through the mixture

Spoon into prepared pan and smooth the top. Cover with 2 layers of plastic wrap and a layer of foil. Freeze overnight

Loosen ice-cream from sides of pan and turn out onto a flat serving plate. Stand for a few minutes to slightly soften. Scatter with extra frozen raspberries if liked. Cut into slices and serve