Pour the milk into a 4-liter / 4-quart heavy-bottomed pot (24 cm / 9.5 inch). Bring it to a full boil over medium heat, 8 to 10 minutes, stirring every minute or two so a skin doesn't form and the bottom doesn't catch.

Turn the heat to low. Add the lemon-water mixture 1 tablespoon at a time, stirring gently. Within 1 to 2 minutes the curds separate and the whey turns clear and pale green-yellow. Turn off the heat.

Line a 25 cm / 10-inch colander with a 45 cm / 18-inch square of muslin and set it in the sink. Pour in the curds, then rinse under cold running water for 1 minute, tossing gently to wash out the lemon taste. Gather the corners, twist, and squeeze lightly, then hang the bundle from the tap or leave it in the colander for 30 minutes.

Unwrap the chhena onto a wide plate. It should feel moist and crumble easily, about 300 g. Knead with the heel of your palm for 5 to 6 minutes until it's smooth with no grains and comes together into a soft dough that doesn't stick to your hand.

Set a 24 cm / 10-inch nonstick skillet over low heat. Add the kneaded chhena, powdered sugar, and cardamom. Stir and fold constantly with a silicone spatula for 8 to 10 minutes, until the mixture softens, pulls away from the sides into one soft mass, and stays pale ivory.

Spread the mixture on a plate and cool for 10 minutes, until it's warm to the touch but no longer hot.

Grease your palms with the ghee. Divide the mixture into 14 portions of about 25 g each. Roll each into a smooth ball, flatten it lightly into a 4 cm / 1.5-inch round about 1.5 cm thick, and press a pinch of chopped pistachio into the center. Serve at room temperature.