First you need to make the chhana (soft paneer or cottage cheese) with the milk and vinegar. Remember that the key idea is to make the chhana soft but not dry. Before moving on to the next steps, you can slightly squeeze the chhana bundle with your hand to make sure there is no water remaining.
In a large pan (about 5 lt would be good) take 1 cup sugar and 5 cups of water. Let them boil to dissolve the sugar, but don’t let the syrup become thick. We need a very thin boiling syrup. Turn the heat off as soon as the sugar is dissolved. Now take the chhana (or soft paneer) in a large plate and add 1 tsp flour, 1 tsp semolina, and 1 tbs sugar to it. Start mixing very gently; at first the mix will be grainy but slowly it will turn into a soft dough. You can use your palm to mash the mix well; this helps make the mix smooth. This step should take 7-8 minutes.
Now divide the dough into 15 equal-sized balls. With the help of your two palms, start making smooth balls. There should be no cracks. Make all the balls and turn on the heat for the syrup to get it boiling. Drop all the balls into the boiling syrup and cover. Let them boil for 20 minutes in high heat. Don’t uncover the pan! For your curious eyes use a glass pan cover :) You can see how the size of the balls double. After 20 minutes of boiling, check the balls by doing the following test. Take a glass full of water and drop one roshogolla into it. If the roshogolla floats then the batch needs to be boiled for another 5-10 minutes, but if it goes to the bottom that means it is done! Just simmer for another 5 minutes and then turn off the heat. Let it rest while being covered for 6 hours.
Enjoy the most famous sweet of Calcutta!
Tip: After 6 hours of rest, take the roshogolla out of the syrup. Then reduce the syrup to about half the quantity by boiling it for about another 10-15 minutes. Check the quantity to decide how much longer you need to boil. Pour this reduced syrup back again over the roshogolla balls.
More pics below!