First, grease an iron kadai with some ghee or clarified butter. After that, put about 3 tbsp of water in the kadai. (Pro tip: Adding a bit of water is crucial as it will prevent the milk from sticking to the kadai while reducing it on a low flame).

Then pour in 2.5 liters of full fat buffalo milk in the kadai. Stir it a bit to cook on a low to medium flame to come to boil.

In the meantime, while the milk comes to a boil, take a steel tiffin box and grease it with ghee on all the sides. Then, place a perfectly cut butter paper inside it.

Now, while the milk is reducing, scratch the sides of the kadai and mix it with the milk stirring continuously. Check the consistency of the milk after a couple of minutes of stirring.

Now, take a pinch of citric acid in a small bowl and add 1 tbsp of water to make a mixture. (Pro tip: Do not use too much citric acid to make this dish, or else it will become cottage cheese and not milk cake).

Add half of the mixture to the milk. Mix and stir it for about a minute and then add the remaining mixture of citric acid to the milk. Do not put all of it at once and do not stop stirring. (Pro tip: If you do not have citric acid at home, use 8 to 10 drops of lemon juice or 1 to 1.5 tsp of curd or dahi).

Soon the milk will start curdling as shown in the below image.

When the milk achieves a nice grainy texture, add 1 cup or 150 grams of sugar to it, once again in small batches. Add 1 to 2 tbsp at a time with one hand and stir the milk with the other hand continuously to ensure the sugar melts and mixes properly. (Pro tip: Do not add all the sugar at a single go, or else it will release water and make the milk cake hard and rubbery later).

Check the color change and thickness of the milk after 3 to 4 minutes of cooking. At this stage, add 4 tbsp of ghee (clarified butter) to the milk, in batches, of course, and mix it nicely every time.

When you notice the color of the milk changing, add 1 tsp of elaichi (cardamom) powder to it and mix nicely. (Pro tip: Adding cardamom powder is, however, completely optional)

When done, switch off the flame of the gas stove and transfer this piping hot khoya very carefully to the steel container you have readied before. Spread and smoothen the surface with a spatula.

Put the lid of the tiffin box immediately.

Place the container on a piece of thick blanket and wrap it with the blanket as shown in the image below. Keep it aside in that way for at least 6 to 7 hours to set properly. (Pro tip: Milk cake sets just perfectly if left overnight).

Open the lid of the tiffin box after 6 hours or the next day. Run a knife along all the sides of the tiffin box. Turn it upside down on a plate and tap it gently with your hands.

Remove the tiffin box gently, and your homemade tasty and sweet milk cake shows itself in its lovely color. Remove the butter paper.

Cut the milk cake into small pieces, put a small piece of pistachio on top of each if you wish to, and enjoy.