Pour the raspberries into a large pan and gently cook on a low heat for 3 minutes, crushing them with a potato masher or fork.
Add the lemon juice, sugar and salt. Stir until the sugar is dissolved.
Remove from pan and set aside to cool. If you want a smooth texture, simply strain the lumps out.
Stir in the yoghurt and milk and mix until combined.
Pour into a dish suitable for the freezer and cover with clingfilm.
Place in the freezer for about 90 minutes until the edges are frozen but the middle in soft.
Remove from freezer, beak into pieces and beat in food processor until soft but not melted.
Return to freezer. Repeat steps 6 and 7 again.
Serve with fresh raspberries.