In a heavy-bottomed pan, heat 1 litre of full-fat milk on medium flame. Keep stirring occasionally to prevent it from sticking to the bottom.
Once the milk starts boiling, reduce the flame to low and let it simmer for about 30-40 minutes, stirring occasionally, until it reduces to half its original quantity.
Add 200 grams of condensed milk and 100 grams of sugar to the reduced milk. Mix well and cook for another 10 minutes, stirring continuously.
Remove the pan from the heat and let the mixture cool down to room temperature.
In a blender, add 250 grams of fresh or frozen raspberries and blend them into a smooth puree.
Strain the raspberry puree through a fine sieve to remove the seeds.
Mix the raspberry puree into the cooled milk mixture and combine well.
Pour the raspberry kulfi mixture into kulfi moulds or popsicle moulds. Cover with a lid or aluminium foil and insert ice cream sticks if using popsicle moulds.
Freeze the raspberry kulfi for at least 6-8 hours or overnight until it is completely set.
To serve, gently remove the raspberry kulfi from the moulds by running them under warm water for a few seconds.