Set a pan with the milk to boil
When it starts bubbling, add the lemon juice gradually and keep stirring. Turn off the flame. You will gradually see the milk curdle and the whey separate
Drain this over a muslin or a thin cloth and rinse with water - this is the chaena. Tie the cloth and hang it so that the remaining water drains off. Make sure there isn't water in the chaena. If there remains any water, the balls won't hold shape while cooking
Transfer the chaena to another bowl and add the food colour (if using). If you are making the traditional, non-flavored rasgulla, do not add any colour to the chaena
Knead it for 10 minutes by flattening and then gathering it, until smooth
You should get a smooth, crack-free dough
Now roll them into lime sized balls and keep covered
For the sugar syrup, add the sugar, rose water and kewra water along with the water to a pot, and heat. If making the traditional sweet, only add cardamom pods to the sugar syrup
When it comes to a roll boil (around 15 mins), add the chaena balls and cover it. Cook them, over medium high heat, for another 12-15 minutes
By this time, they would have doubled up in size. Turn the flame off and let the pot (with the rasgullas) cool down. Do not open the lid until the pot is cooled. Thereafter, remove and serve