Heat the milk in a deep non stick pan. When it comes to a boil, add the lemon juice and stir till the milk curdles. Strain and immediately refresh in chilled water.
Put the chenna through a muslin cloth and squeeze till all the water is drained out. Mix the saffron in one tablespoon of warm milk.
Knead the chenna well with your palms. Add sugar substitute, green cardamom powder and saffron milk and knead again.
Steam the mixture in a steamer for ten minutes.
When slightly cooled divide into twelve equal portions and shape each into an oval shape.
When cooled garnish with pistachios and serve.