Pour the milk into a heavy-bottomed 4-quart saucepan. Bring to a boil over high heat, stirring to keep the bottom from scorching. When it starts boiling up in earnest, remove from the heat and promptly strain the lemon or lime juice into the milk, stirring it gently. The milk should rapidly separate into clouds of white curd in a greenish-yellow whey. (If this doesn’t happen, add another spritz of juice.) Let stand for 8 to 10 minutes.*
Line a strainer or colander with tight-woven cheesecloth or other clean cotton cloth, set it over a deep bowl, and use a skimmer or shallow ladle to carefully lift out the larger clumps of curd into the cloth. Very gently pour in the whey with the remaining curd.
Let drain for a few minutes. Tie the corners of the cloth into a bag. Holding the bag by the tied corners, briefly rinse the curd under cold running water to remove a little of the lemon taste. Gently squeeze the bag in your hands to press out some of the water. Now you can either hang it up to drain further until it is a little softer than cream cheese (usually about 1½ to 2 hours; suspend it on the kitchen faucet or a wooden spoon set over a deep bowl) or speed the process as follows: Flatten the bag of curd into a rough disc or rectangle, put it on a plate, and cover it with another plate. Place a weight (a heavy can, a couple of large beach pebbles) on the top plate and let stand for about 30 minutes, periodically draining off any overflow. It can then be used as is, but will be easier to work with if you cream it with a large wooden spoon in a bowl or with the heel of your hand on a flat work surface. Imagining that you are creaming butter for a cake or putting a pâte brisée through the stage called “fraisage,” work the cheese very, very smooth a little at a time. If you are not using it at once, pack it into a container and refrigerate, tightly covered. It is extremely perishable and should be used within 3 to 4 days.
Makes about 8 ounces (1 cup) chhenna, 7 cups whey
From Milk: The Surprising Story of Milk Through the Ages by Anne Mendelson (Knopf, 2008)