Start boiling the entire milk in a deep vessel till a bubble comes from the milk and then reduce the flame.
Start adding Lemon Juice or Vinegar to the milk and stir with a ladle to mix the souring agent properly to curdle the milk.
The Milk will start curdling within a ½ minute or so and the water will also start separating from the Curdled milk.
Switch the flame off and cover the vessel with a lid and wait for 5 minutes.
Take a Strainer and discard the entire water from the curdled milk and then take the Curdled milk in a fresh Muslin cloth and then tie a knot to close the cloth containing Curdled Milk or Chana from every side.
Now Place it in a flat place preferably within the sink and put a weight on the cloth to press the Chana to discard water from it for around 30 minutes.
Now remove the Wight and open the cloth and then take the Chana out from the cloth.
Cut Chana into small Squares for making Chanar Dalna.
Making of Chanar Dalna
Cut Potatoes into medium-sized Cubes and chop tomatoes roughly.
Make a paste of Ginger and add Cumin powder to that paste and mix properly.
Mix both Turmeric Powder and Red Chilli Powder with a little water to make a paste.
Now Take Oil in a Pan and heat the oil properly and then start frying Potato cubes till those turn Golden Brown keep those aside after frying.
Now fry Chana Cubes from all the sides in the same oil. The Cubes of Chana should turn Bright Brown after frying. Strain Fried Chana from the Oil
Temper remaining Oil with Bay leaves, Dried Red Chilli, and Cumin Seed and cook for ½ minute and then add chopped Tomatoes in the tempering and cook for around 2-3 minutes in low flame till the raw smell of Tomatoes emits completely.
Now add Ginger-Cumin Powder Paste and Turmeric-Red Chilli Powder Paste to the Pan and mix properly with a ladle and cook for around 2 minutes.
Add Sugar and Salt to the mixture and add 2 Tbsp. of Water as well and cook till oil separates from the mixture.
Now add 3 Cups of Water and coconut milk (optional) and also the fried Potatoes and Fried Chana to the Mixture and mix properly.
Cook in Medium flame for 10 minutes while covering the pan with a Lid.
Add Bengali Garam Masala Powder and Ghee to the Gravy and mix properly.
Switch the flame off and give the Curry a rest of 5-7 minutes before serving.
Chanar Dalna can be served with either Rice or any Flatbread including Roti, Luchi, Poori, Kachori, or Radhaballabhi.